Whatever Can Happen Will
by FlightyFelon
Summary: Sans wakes up after yet another reset. However, something is different about this playthrough. Something is loose in the time stream and is wreaking havoc with the way things are meant to be. Older!Frisk helps Sans face his past as they travel between AUs in search of a way home. (Very Head-cannony!) AUs so far: UNDERFELL, UNDERSWAP, BROMALGAMATE.
1. Chapter 1- RESET

**Hello Readers! This is my first foray into Undertale fanfiction and I'm a bit rusty (so be gentle (8o8) ).**

 **WARNINGS: Some harsh language (especially from Sans), Alcohol(?) abuse. Talk of suicidal thoughts. Probably some angry smooching. Definitely angst and major character death.**

 **SPOILER ALERT: Basically every conceivable spoiler might rear its head in this story, since the premise is that some entity is screwing with the timelines and garbling them up. In fact, to get the most out of the story you'll probably want a very intimate understanding of the Undertale MetaGame including the neutral, pacifist and genocide runs.**

 **DIFFERENCES FROM POPULAR CANNON: Female Frisk. Older Frisk (perhaps around 16-17 y/o?) so all the monsters are scaled up to the same relative heights of the sprites in game. This means that Sans is just under 6 feet tall and rather menacing.**

 **May also delve into some popular AUs (possession, underfell, bromalgamate etc.)**

 **In summary: All aboard the feels train! Choo Chooooo~!**

* * *

-WHATEVER CAN HAPPEN WILL-

CHAPTER 1- RESET

Sans shot bolt upright on the couch. There was a sickening sensation of disorientation that crashed over him in waves and he knew that if he'd had guts he'd be puking them up right about now.

Heavily, he tried to roll his bones off the lumpy cushion and stand but the nausea was too much and he ended up sprawling onto the floor.

"paaap-?" He moaned weakly, feeling gravity shift like he was using his blue magic. Images began flashing through his mind faster than he could make sense of them, juxtaposing and branching apart and coming together and falling apart... Becoming dust.

No. God no. Not again...

"p-aaaap?" Sans felt the fear next; crawling on his back and sinking into his marrow. They had been there. On the Surface. They'd been free... and... and...

"BROTHER? IS THAT YOU? AWAKE ALREADY?" Papyrus' loud voice filtered in from the kitchen. It's grating quality soothing to Sans' ears nonetheless. Whatever new Hell he'd just woken up into, at least his brother was safe. For now.

Papyrus leaned out of the kitchen, clutching a pot of boiling water and spaghetti to his chest (he didn't seem to notice how it was singing his Battle Body chestplate). The lanky skeleton's expression flickered from its regular enthusiastic grin through enthusiastic alarm and quickly into enthusiastic consternation at finding his lazybones brother on the floor.

"SANS. I'M AFRAID YOU'LL HAVE TO WALK TO THE KITCHEN LIKE A NORMAL MONSTER. IF, YOU WANT ANY OF MY DELICIOUS SPAGHETTI, THAT IS. NYEH HEH HEH!" Papyrus was stirring the scalding water so vigorously it was sloshing out the sides of the giant pot.

"you got me." Sans pushed down the last of his lingering queasiness and fell back on his favourite self-defense mechanism. "but the smell of your cooking just had me..."

"SAAAAANS!" Papyrus started stirring so hard that full, semi-cooked spaghettos were flying out of the pot.

"floored."

"BROTHER I DISOWN YOU!" Papyrus cried as he swept back into the kitchen, smiling despite himself.

...

...

Slowly, carefully, Sans pushed himself out of his prone position and rested awkwardly against a lumpy armrest. Despite being a skeleton-monster, his magically-chubby belly sat heavy on his frame. Sans drew a bony hand across his face and then wiped himself off with well-used handkerchief when he found that he'd been sweating uncontrollably.

Mustering what was left of his determination, Sans pulled himself back up onto the cushions and felt himself sink into the couch's green polyester embrace. Winded from even that small exertion, he decided that what he needed was a good deal less Grillby's and a good deal more exercise. He felt tired at the prospect.

However, he was avoiding the issue. The human, that damn FREAK had done it again. Despite its promises and friendship and mercy. After doing everything perfectly right it still wasn't satisfied. WHY?! What did it want? Sans tried to remember how many times he'd awoken on this same couch, to the quiet tune of Mettaton re-runs and the joyful whistling of his brother cooking as if nothing had happened. How many times had that thing RESET?

He was alarmed to discover that he'd lost count.

"hey paps. going for a walk, okay? would you pack up my spaghetti for later?" Sans got up and slouched towards the front door, the time-sickness already fading.

"VERY WELL! BUT REMEMBER. LATER WE'RE GOING TO GO RE-CALIBRATE THE PUZZLES. I HAVE A FEELING. THAT TODAY WILL BE AN IMPORTANT DAY."

"i know." Sans replied quietly and stepped out into the cold in nothing but his usual blue hoodie, track shorts and fuzzy slippers.

...

In the quiet of the house, Papyrus stopped stirring and stared at the closed front door. He felt his gloved hand shaking around his wooden spoon so he tightened his grip to make it stop. There was that feeling again. Like he had just been somewhere else, doing something else. Something happy... he thought? He'd felt so happy.

He had been about to continue his cooking when he felt a shiver go down his spine and to his surprise he discovered that he couldn't move, not even an inch.

A low whine escaped him as he felt his soul clench where it lay nestled inside his ribs. He'd wanted to call out for his big brother, but he couldn't even do that. Then, to Papyrus' mounting horror he became aware of a presence in the kitchen with him. Something dark shifting in the peripheries of his vision.

He tried calling out again for Sans but this time he couldn't even muster so much as a whimper.

.

.

* * *

.

.

Sans didn't bother with taking any of his shortcuts today. He knew he didn't have to hurry. Besides, it felt kind of good to get from place to place one foot at a time. Tiring, but good.

He knew he had a good while before THAT FUCKING HUMAN stumbled out of the Ruins so Sans took a detour into Grillby's. Sans may not have been as tall as his brother, but he was still big as far as monsters went. At a bit under six feet to the crown of his head and sturdily built, he had to angle himself to fit through the bar's door. His earlier resolution to eat less greasy food crumbled into dust as he settled himself onto his usual stool.

dust... _fuck_.

Apparently picking up on Sans' distress, Grillby slid a bottle of ketchup towards him across the well-polished bar. Also apparently, Sans was looking worse than he thought because the ever-astute barkeep also presented him with a small shot of some hot mustard, the hard stuff.

"thanks, grillbz." Sans gave him his patented grin in appreciation, to which Grillby simply shrugged and pushed his spectacles further up his non-exisetent nose.

The bar was fairly empty right now (as it always was at this point in the timeline) since the royal guard-dogs were all off sniffing out trouble in the mountains. The other patrons seemed relaxed, however. At peace with their lots in life and content to while away the unchanging ages in good company. Sans envied them a little as he tossed back his hot mustard and let the warming numbness stop the overactive gears in his mind from grinding quite so painfully.

He had been halfway through his second bottle of ketchup and his first burger (so he'd caved, alright?)when he heard it.  
A shout.

 _Papyrus' shout._

The lights in Sans' eyes contracted to pinpricks in fear. That had never happened before! Sans nearly fell out of his seat on his way to the door, knocking over the dogs' poker set-up in his panic.

"Hey Sans buddy, what the matt-" The flytrap monster was cut off as the door slammed closed behind him.

The wind outside had picked up noticeably and he could feel the little crystals of blown snow glancing off his exposed bones. Not for the first time Sans was glad he couldn't feel temperatures. It was strange, though. He could have sworn that this blizzard wasn't due until at least tomorrow.

The big-boned skeleton stood perfectly still on the quiet, snow-scoured streets, all senses on high alert. At least as alert as they could be through the haze of monster-alcohol. Papyrus was right, Sans thought sullenly. He really was turning into a slob.

Just as Sans was about to attribute the shout he'd heard to his drunken, stress-adled mind he heard it again. This time, however, he was able to recognize it as a shout of... joy? It was coming from the direction of the mountains and the Ruins.

Feeling rattled, Sans ducked behind the Librarby and into one of his shortcuts. The one he knew would take him straight to the big stone doors of the Ruins.

They'd been opened already. Little wings of snow-bare rock were visible where the double doors had swung outwards, though they were quickly being filled in by the mounting blizzard. Side-stepping, Sans re-appeared near Papyrus' electro-maze and was shocked to find not two, but three sets of footprints already leading through the maze, one dainty, one obviously his brother's and a third padded and overlarge.

 _what?_

Sans flitted from space to space, feeling the drain on his magic keenly as he watched with growing horror as he saw the evidence of the changes in the timeline.

The snowman had been untouched, Alphys' tile puzzle had settled on a genuinely random puzzle which had apparently been solved. The snow dodecahedron near the 'ball' game was now obviously an octadecahedron, and Papyrus' super-deadly human trap had actually been sprung. (Although the annoying dog was still dangling from its rope, seemingly as confused as Sans was).

Finally, Sans stumbled back into Snowdin, practically collapsing from exhaustion. In fact, yes. He did decide to collapse from exhaustion as he dropped to his hands and knees and felt utterly blind-sided. It was all different. It was all new.

Before he could stop himself, Sans felt a manic grin draw at the corners of his mouth. He hadn't felt so alive in years! He started laughing, then he started crying and then he started hiccuping as he tried to do both at once, fairly certain he was finally losing his mind.

"Hey there. Are you alright?"

Sans was dragged out of his internal spiral by a soft, timid voice. He knew that voice. It was the voice that haunted his worst nightmares, and his best ones. Frisk.

"SANS? WHAT ARE YOU DOING? BUILDING A SNOW FORT WITHOUT ME?"

Sans looked up to find the human girl standing timidly before him, daintily posed with one hand outstretched as if to help him up. Despite his exhaustion, he slapped it away and struggled to his feet without assistance.

 _Who did the human think she was kidding?_ They both knew that the moment Sans let down his guard was the moment he'd find a knife between his ribs.

"THAT WASN'T VERY NICE!" Papyrus chastized as he drew closer. "DON'T YOU KNOW HOW TO GREET A NEW FRIEND?"

Sans had been about to make a biting retort but Papyrus' words made it stick in his throat.

 _This was wrong._

Despite all evidence that this human child was as cold-blooded a demon that had ever walked the Underground, Sans was surprised to discover the first hint of tears brimming in their young eyes. Though perhaps... not so young? Sans gave the human a long, appraising look up and down. Though she was still young and frail-looking, the girl was nearly as tall as Sans' chin, and that was even as he tilted his skull back menacingly. He could even see the first curves of womanhood through Frisk's formless striped sweater.

The throught briefly crossed his mind that perhaps this was Frisk's actual age, what with all the endless SAVES and RESETS.

"sorry, uh, bucko?" Sans stammered, his mental processing capacity thoroughly spent. He realized dispairingly that he had forgotten his palm-sized whoopie cushion at home, but under Papyrus' enthusiastically disapproving glare he had no choice but to stick his hand out to shake.

"real... pleased to meet'-"

"PBBBFFFFFFFFFTTTTTHTHHHHBBBBBTTT...PBFTHT... Poot."

Both Sans' and Papyrus' eyesockets went wide at the rude noise, though for very different reasons. Frisk threw her head back with laughter, a sound that Sans had never heard her make before.

"HUMAN. THAT WAS..." Papyrus managed.

"Well done, My Child." A new voice, tinged with suppressed laughter preceded the newest change in the timeline. Sans knew that voice too, and not just from his endless knock-knock joke sessions.

Lo and behold, Toriel herself padded up to the group and placed a hand on Frisk's beaming head (apparently having forgotten Sans' rudeness earlier). Tori's silky, white fur rippled in the rising wind but she didn't seem to mind the cold, even though she had ABSOLUTELY no business being here.

"have we... met before?" Sans asked, knowing even as the words came out of him mouth that he was reading from the wrong part of the script, so to speak.

Toriel's big, ruddy amber eyes opened a little wider in recongition and a glad smile spread across her muzzle. Despite everything, it still warmed Sans' heart to see it.

Before they could make their proper introductions, however, Papyrus threw a bone in things and announced: "THE HUMAN CHILD IS COLD. AND SHE OWES ME A DATE. CAN WE TALK MORE AT HOME? OVER SPAGHETTI?"

There was a general agreement and Sans found himself wandering after the group of his friends (and not-so-friend) towards their home. He was still reeling from the fact that Papyrus and the human had already fought and he hadn't even been there to help the human over that last, gigantic bone in Papyrus' not-so-special attack with his blue magic. He hadn't been there to watch over his brother, the one reason he hadn't jumped into the Hotland lava years ago.


	2. Chapter 2- COLD HANDS

**Hope you guys are enjoying the story so far. :) Some spoopy stuff goes down in this chapter and Sans learns what it feels like to be truly defenseless for the first time in in.. well... a long time.**

 **I'm also very open to prompt suggestions and reviews so send some my way if you like.**

 **EDIT: I extended the chapter, since it felt too short. Also moved the original Chapter 2 into Chapter 1 to give first-time readers a little more idea of what the story will entail :) So, uh, if you're returning to the story and feel confused. That's why.  
**

* * *

.

.

CHAPTER 2- COLD HANDS

Sans cracked the cap off a bottle of ketchup as he sat back on his lumpy couch with Toriel beside him. He had offered her one but her eyebrows had climbed so high up her forehead they'd lost themselves between her floppy ears. Ah well, it was an acquired taste.

Regardless, the two of them watched as Papyrus took Frisk on a tour of the house, examining each minute detail as if it were some sort of quirky museum.

"ahem... knock knock?" Sans began, not sure how else to, really. He'd never really had the chance to actually get to know the former Queen of Monsters beyond a few moments behind the King's throne room. The sight of her, prim and regal on his grubby couch was making him anxious.  
Toriel grinned back at him, "Who is there?" She asked.

"waiter."

"Waiter who?"

" **waiter you doing outside the ruins**?" Sans finished, not able to keep the edge of fear out of his voice. His inner turmoil must have shown on his face as well as Tori's eyes widened slightly.

Noticing this, Sans quickly drew back into himself, cursing himself for scaring her like that. They'd only just met after all and here he was being a total creep and-

"SANS! GOAT LADY! THE HUMAN AND I WILL NOW. BEGIN OUR DATE! NO INTRUSIONS, PLEASE!" Papyrus all but screeched from upstairs where he was about to enter his room with the human. Frisk had a long-suffering smile plastered on her face but seemed to be enjoying herself.

As Papyrus slammed the door shut behind them Sans turned back to Toriel, about to begin his apology from being such an ass.

He was surprised to discover her staring unblinkingly at her hands, looking terrified and confused.

"I-I'm... not sure." She peeped, looking upset and sheepish. "I... never left them before... not even for the other children. Maybe... I just couldn't take it... anymore?"

Sans set his ketchup bottle down on the floor and twisted awkwardly to face her.

"hey. don't be like that. didn't mean 'ta push ya." He extended a bony hand to her but she practically flinched away from it.

Then, realizing what she'd done, the Queen seemed to snap out of her stupor.

"Oh. I am so sorry. I do not know what came over me just now. Following the human was a good idea, I think. She never would have made it through Papyrus' puzzles and attacks without me." Now that Tori had snapped back to her normal self, it was hard to imagine her with the haunted look she'd had just a few moments earlier.

However, Sans was a hard skeleton to fool.

"it's fine, tori. i need to check on something, alright?" Sans hefted himself out of the cushions and downed the rest of his ketchup on his way to the door.

"Wait! I do not believe I ever told you my-" Toriel was cut off as Sans slammed a door in someone's face for the second time today. Pap was probably on to something about him needing to improve his manners.

Still feeling exhausted from flitting around Snowdin earlier, Sans slogged mundanely to the secret room behind his house and fumbled with the keys in the lock.

"stupid keys..." he muttered, trying the obstinate things in different orientations even though he'd never had any trouble with them before.

...

"{S-A-N-S}"

...!

Sans felt as if cold fingers had laid themselves on his shoulder blades. Which was odd, since he couldn't feel temperatures. He really didn't want to turn around.

Reaching for his ever-simmering magic, he was terrified to feel... nothing? Just the same, cold emptiness that was now settling over him like a shroud. He tried again to summon the blue fire but to no avail.

With a snarl that sounded suspiciously like a squeak he whipped around, brandishing the keys like a mundane weapon and-

Nothing.

Just the empty space between his house and the silent forest. The stillness was palpable. Even the snowflakes didn't seem to want to fall, gently descending in fluffy clumps.

"who's there?" Sans whispered, trying to grasp his magic once again and nearly falling to his knees in relief as it responded. Blue flames licked at the inside of his left eyesocket, comforting and powerful. Despite the sharp pain of keeping his magic concentrated like this, Sans was too worried what would happen if he let it go. Without his magic he was nothing. Defenseless. Useless.

He wouldn't be able to protect Papyrus when the human inevitably...

Sans let his blue light illuminate his way down the stairs to his personal lab (His key had worked as soon as he'd tried it, this time). Swiftly, he pulled the tarp off the rectangular machine sitting in the corner of the room and pored over the readouts in the lurid, blue light.

None of it was making any sense. He had never seen readings like this before. Not since...

 _oh god._

Sans dropped the papers on the floor and spun towards his save box, unclasping the lid with shaking phalanges. Inside, nestled among his countless notebooks, above an alternate Papyrus' dusty scarf, sat a single square of paper. On it was scrawled only a few words:

 **'he's** **back!  
** (this was then crossed out hastily)

 **gone. trust the human.'**

It was undeniably his own handwriting, and as he rubbed his thumb-bone across the dark ink it smeared across the page. Whatever had happened, it was recent. Probably right before the RESET. Sans was glad his alternate self had had the space of mind to make this note. However, the fact that he'd been in his lab right before the lights went out probably meant he'd been expecting it. How many times had he not? How many times had he run this same path completely unaware?

The blue light in his eyesocket leapt with his fury at being treated like a child's plaything.

 _'trust the human?_ ' Please. Now that was real funny. But... they did seem like they'd changed emotionally in addition to appearing physically older. No. That _freak_ would never change.

San's magic rumbled in his chest and he felt his GasterBlasters straining at the void where he kept them, waiting.

 _'wait. gaster.'_ Sans felt his anger gutter and die along with the light of his eye, plunging the lab into darkness. That's who the note was referring to. Somehow Gaster was back and was fucking with the timeline. Modding it. It made at least a little sense, he thought. But what had he meant by: 'gone'? He supposed he'd just have to figure that part out fast. Before anyone else was put in more danger.

Quickly and by the light of his desk lamp, Sans added his new revelations and notes to his safe box which were far less cryptic. This way, he'd be able to reach the same conclusion in any timeline.

"there." He said when he finished, somewhat satisfied.

Still, as he ascended the steps to the outdoors, he couldn't help but feel those cold hands looming over him, like shadows in the void.

...

As Sans re-entered the house it took a moment to get re-adjusted to the up-beat atmosphere. Papyrus was treating Toriel and Frisk to some spaghetti, probably to let the human down easily now that she'd been friend-zoned.

"SO THE HUMAN AND I ARE DATING NOW." Papyrus announced without preamble.

Sans stopped mid-step.

"huh?" Sans was getting sick and tired of being broadsided like this. In a way it was a little refreshing, but mostly is was just annoying.

"YES! DATING! GOING ON DATES AND DOING DATE THINGS!" Papyrus continued as if nothing were wrong with this situation. Which, Sans rationalized, there wasn't. Except for the fact that his Papyrus was in a blossoming relationship with that _dirty brother killer_. And that said dirty _fucking_ brother killer was currently doing their best to work their way determinedly through Papyrus' inedible spaghetti.

"you... don't say." Sans passed up the prospect of pasta entirely and pulled another bottle of ketchup out of a cabinet.

"I DO SAY! AND- HEY! HOW MANY OF THOSE HAVE YOU HAD TODAY, SANS?!" Papyrus rattled, standing akimbo in his 'Smooch the Cook' apron. As an answer Sans merely tilted the bottle up and chugged the whole thing down, feeling a little better, but not much. Then he noticed Frisk's spaghetti was garnished with heart-shaped bits of glitter.

He was in the middle of grabbing another bottle when he felt his brother's gloved hand close on his forearm-bones.

"NOT TONIGHT, SANS. PLEASE?" Papyrus gave his best attempt at a whisper.

Everyone was staring at him now, which was not a situation Sans was very comfortable being in. Toriel seemed unsure of what she should do with her hands and settled on holding onto her cutlery so hard it was warping. The human gulped down a noodle with some difficulty and stood up.

Once again, Sans marveled at her developed body and how time had lent her scrunchy, childish features a soulful depth.

"It's okay, Papyrus. I really should get going." She said, already organizing her pockets with the help of her cellphone.

"Are you sure, My Child? Wouldn't you rather stay here for a while?" Toriel practically bleated, rising to her feet herself.

Frisk, determined creature that she was, simply shook her head and picked up her old stick from where it lay beside the door.

"WAIT! HUMAN! DO NOT THINK YOU WILL BE LEAVING THE GREAT PAPYRUS BEHIND! I WILL CATCH UP TO YOU SHORTLY!" Papyrus called after her and Toriel as they left.

...

"LOOK AT WHAT YOU'VE DONE, SANS!" Papyrus shouted once they were alone, releasing Sans' arm and gesturing so expansively his long fingers brushed the ceiling. "WHAT IS WRONG WITH YOU?!"

Sans tried his best to wrangle his usual grin back onto his face but it wasn't cooperating.

"paps, look. I-"

"DON'T YOU PAPS ME!" Papyrus stuck one bony finger at where Sans' nose would have been. He hadn't seen Papyrus this mad in a long, long time and even then his anger hadn't been directed at him.

"just listen, will ya?" Sans snapped back, swiping aside the accusing finger. "that human's no good. no good for you."

Sans balked a little at the hurt expression that flashed across Papyrus' face but he was scared. And perhaps Papyrus should be too... but not of him. Driving Papyrus away would help no one.

"sorry. that came out wrong." Sans backpedaled, running a hand over his suddenly-sweaty skull.

"GOOD FOR _ME?_ " Papyrus spun around and started gathering up the barely-eaten spaghetti, probably so Sans wouldn't be able to see his face. _shit._ He'd gone too far this time.

There was a stretched silence as Papyrus composed himself, the Tupperware lids clattering as he tried to seal the pasta into its new prison.

"WHO ARE YOU. TO SAY. WHAT'S GOOD FOR ME?" This time Papyrus actually did succeed in whispering, which made only made his words all the more forceful. Sans felt like he'd been punched in the gut. "I LOVE YOU. I REALLY DO. YOU JUST MAKE IT SO HARD SOMETIMES, SANS. EVER SINCE WE LEFT THE CAPITAL. YOU'VE BEEN STRANGE. LAZY. ANGRY."

Papyrus turned his head away from the fridge , his expression in shadow.

"YOU ACT LIKE YOU KNOW SOMETHING OTHER PEOPLE DON'T."

Sans had no response to this. All he wanted was to escape. As usual.

"I AM GOING TO FOLLOW THE HUMAN. AND WE ARE GOING TO DATE. AND YOU-" Papyrus jabbed his finger in Sans' soft belly, making his point. "CAN DO WHATEVER YOU LIKE. AS ALWAYS."

Sans didn't even have a moment to respond as his tall, uncharacteristically angry brother stormed past him and out the door, not even bothering to slam it.

It was dark outside.

Snow was blowing in onto the welcome mat.

Sans slumped to the floor, facing it. He'd really fucked things up this time.


	3. Chapter 3- ECHOES

**Frisk likes holding hands. :) She maybe also likes Sans.  
**

 **Also, on the last chapter I had a question regarding Frisk's gender. In-game they're never specified as a boy or a girl. The fact that I always saw them as a female was purely my own projection. In this fic, I continue writing them as a girl because it jives best with my personal cannon that Sans is male and hetero.**

 **If anyone is offended by these presumptions I'm sorry. ;o;**

* * *

ANYTHING THAT CAN HAPPEN WILL

CHAPTER 3- ECHOES

Toriel didn't say anything when the taller skeleton brother caught up with her and Frisk on their way to Waterfall. After spending time with Papyrus as they solved his dastardly puzzles and traps she had come to think of him as a cheerful, happy-go lucky monster. Seeing him pouting like this, barely constraining his long strides to keep pace with them was strange. Perhaps Sans wasn't the kind soul she'd thought he was since that fateful day at the Ruins door.

"It's okay Papyrus." Frisk said finally, slipping her tawny hand into his gloved one.

The lanky skeleton sighed deeply, clearly putting up a brave front.

"IT'S ALRIGHT, HUMAN. SANS JUST HAS THESE MOODS SOMETIMES." He said, his voice almost reaching its usual shouting volume again, which was a good sign. The human gave him her best smile and Toriel was amused to see Papyrus blush a little at the sight of it.

By now they had entered a strangely-lit corridor that made their shadows stretch out before them. The path was covered in overgrown grasses and the cavern beyond was dank with huge stalagmites that seemed to rise like dark specters from the still pools.

"THANK YOU, HUMAN." Papyrus gave the girl's hand a little squeeze before gently pulling his hand away and taking out his cellphone. "I JUST THOUGHT OF SOMEONE WHO WOULD MAKE OUR ADVENTURE. TRULY SMASHING!"

Papyrus dialed in the number and put the phone to his ear, waiting.

Ring...

Ring...

Ring...

 _But Nobody Came._

Papyrus stared at the phone accusingly for a moment before redialing. The second try had the same result.

"THAT IS... UNUSUAL. OH WELL! WE'LL SEE HER LATER, I GUESS!" Papyrus gave a shrug, already returning to his normal, optimistic demeanor. Toriel felt her soul lighten a little. She still had a strange feeling that something wasn't quite right but for now she felt filled with determination by the adventurous atmosphere.

Sans tracked the trio from behind one of the stalagmites, a choice people-watching spot he'd discovered back when he and Pap had first moved to Snowdin. Back when he hadn't known the exact paths of every monster in the Underground down to the minute, that is.

The big-boned skeleton was still a bit nervous about using his magic after what had happened behind his lab earlier. However, he wasn't exactly what you'd call agile without its assistance. As he tried to maneuver between the stone pillars after the intrepid party he knocked a loose stalagmite and sent it crashing down.

He'd barely been able to dive behind the base of another pillar before Frisk's all-encompassing stare swept towards him. Sans cringed as the sound of falling rocks slowed to a trickle and he was pinned there by... what. Fear? No, he wasn't really afraid of the girl, _right_? He just didn't want to be caught snooping. That was it. Sure.

From then on he decided to take his shortcuts.

That was why he was already there when the rest of the travelers arrived at the echo flower grotto.

He sat lazily on a flat rock as he watched them approach, twirling a sopping-wet tutu around one forefinger. It had been caught on the stem of a water sausage instead of being tucked away in the tall grass as it should have been.

"here ya go, kiddo." He said as he tossed the tutu at Frisk's feet where it fell with a wet squelch. "that's 10def better than that old bandage you've got."

Toriel and Papyrus were eyeing him suspiciously, but Frisk seemed overjoyed at the gift, quickly pulling it up around her waist and twirling it this way and that (getting the others soaked, too).

"Thank you!" She chirped, beaming. Sans thought she actually looked pretty cute in it.

"sure thing, bud."

"Wait a moment." Toriel said quietly as she put a furry palm on Frisks shoulder to hold her still. Sans thought for a moment that Toriel was going to make Frisk reject the peace offering but then he got a better look at her face.

"I believe I recognize this garment." Toriel's eyes had gone dark and her normally smiling muzzle drooped. "One of my... Children. This must be where they..."

Frisk put a compassionate hand on Toriel's cheek, wiping away a sudden tear.

"WHAT IS WRONG? IT IS JUST AN OLD TUTU, RIGHT?" Papyrus asked, coming to lay an arm over her broad back.

Sans got down off his perch and approached, trying to puzzle out what had caused this emotional reaction.

Then he felt something shift and click inside his head, unlocking paths he couldn't remember treading but could feel that he knew very well:

* * *

{{{{{a younger Sans walked alongside the small human in her fluffy, pink dress (she'd called it 'a tutu' and he'd responded with: "bless you", making her giggle) and tight shoes that made her seem to walk on her toes. He held her hand gently, guiding her among the echo flowers that whispered wishes and lamentations, but were probably now spouting snippets of their conversation as they walked on.

"You're really nice for a skeleton." The girl said, taking his uncertain hand in hers and swinging it back and forth cheerfully.

"ya... think so?" Sans muttered, still a bit nervous around her. After what had happened to the last human he'd tried to protect, he still had lingering questions about their morality. The last boy, with his tough-looking bandanna and gloves had turned out to be a monster. And not the good kind. It was a good thing he'd been so weak.

As Sans retracted his hand from hers he was sure he'd find it covered in blood. It had taken so, so long to wash it all out of his bones. He was just an assistant scientist for crying out loud. He couldn't handle this level of responsibility.

-The memory skips-

Undyne, but much younger blocks the way.

"please. let us through. this kid never hurt anyone. she deserves to go home." Sans had always been intimidated by the newest leader of the royal guard with her black eye patch and lean muscles. Some monsters said she could suplex a boulder, if she wanted to.

"Wish that I could, Sansy." Undyne shook her head, making her flaming orange hair stream behind her like a war-banner. "Asgore's orders."

Sans tried to stop the powerful monster from approaching further by stepping bodily between the two of them, arms splayed.

"kid. just run, okay?"

But the girl seemed too terrified to flee.

"Don't wanna hurt ya." Undyne picked Sans up by the front of his hoodie and threw him aside (he'd been much slighter then, having never taken the time to eat properly during his research days). All that was hurt was his pride as he slammed against the cavern wall, his 1HP still intact, but barely.

Sans lifted his hand, trying to find the magic he'd never been able to reach. Nothing. Useless.

All he could do was watch in horror as the human's yellow-tinted soul manifested on the front of their chest. Not nearly determined enough.}}}}}

* * *

Sans staggered back suddenly, clutching at his ribs. Back fully in the present, Sans tried to remaster his grin while Papyrus was still absorbed in consoling Toriel. Only Frisk seemed to notice. Empathetic sadness clouded her dark eyes, even if she couldn't know why.

Quietly, she pulled the tutu down from around her hips and handed it to Toriel gently. Then, she approached Sans with that understanding look he had always found enticing and infuriating. Right now, however, he found it strangely comforting.

"i can't believe i forgot..." Sans said, so quietly that only Frisk could hear him.

"You wanna talk about it?" Frisk asked, seeming to peer up at him despite them being almost the same height.

Sans made no reply, simply shoving his hands in his pockets and looking away.

She nodded like he'd said what she'd wanted to hear.

"Hey guys," she walked back up to Papyrus and Toriel. "Is it cool if Sans and I go ahead for a bit? I want to talk to him about something."

Toriel's hackles raised defensively for a moment and Sans was sure she'd object, but something in Frisk's stare must have reassured her.

"Of course, my child. But be careful." Toriel said softly, her burgundy eyes flickering over Sans' white ones.

Sans was a little hurt at her mistrust, but he supposed he'd earned it. He'd knit his socks, now he had to wear them.

.

.

The grotto was silent but for the irregular dripping of water falling from the ceiling into the magical, radioactive-blue waters below. Neither Sans nor the human spoke as they wound their way through the labyrinth, stopping periodically to listen to the voices of the echo flowers.

"Do you have a wish, Sis?"

"Yeah but... you'd just laugh."

Frisk looked so serene, lit from below by the eerie teal light. She held out a hand to Sans, palm down. He looked at her with hollow eyes, mistrustful.

But in that note he'd found, his past self had told him to trust the human. And if he couldn't even trust himself, he was truly lost.

"No! I promise I won't!"

"Well I wish..."

Tentatively, Sans let the human girl take his hand and weave her soft fingers between his boney ones. Frisk smiled at him and against his better judgement, Sans felt the corners of his grin lift a little, though he was still wary.

 _"...To stay down here forever, with everyone I love."_

Frisk stopped walking abruptly and halted Sans as well since they were still holding hands. Sans hadn't felt this awkward in a very long time. He'd become so accustomed to knowing exactly what was about to happen, becoming more and more passive, more lazy with each RESET. Since nothing he ever did seemed to change anything.

Frisk was the one to break the silence.

"How much do you remember?" She asked, her expression perfectly frank. Sans felt her fingers close a little tighter on his, probing.

The skeleton took a long moment to consider his words before replying, since he didn't want to give anything away that might be used to hurt him. Or his brother.

"less than you, prob'ly," he shrugged. "but enough." At that last word his pupils diminished into the tiniest pinpricks, like distant stars.

Frisk swallowed audibly in the quiet grotto and Sans was glad that he wasn't the only one feeling uncomfortable.

"That's too bad." Frisk said softly, looking off at the crystal-dappled walls. "In the last timeline, we ended up getting really... close."

Sans barely contained a snort of derision.

"you 'n me? don't kid yourself, bucko. i'll be burning in **hell** before i try to be friends with a **freak** like you."

Genuine hurt flashed over Frisk's features, making her appear to draw into herself.

"Things are different now." She whispered, almost hopefully. "Each timeline is different now. I made sure of it-" Frisk stopped abruptly, realizing what she had just said. "I-"

Sans reacted in an instant. With supernatural speed and strength his grip became iron on her hand and with a jerking motion he whipped her body around and slammed her back-first into the nearest boulder.

-CRACK-

 _ **"what did you just say?"**_ Sans snarled. His left eye was burning suddenly, and he could see the unbridled terror in the human's eyes as she struggled for breath, lit in high contrast by the torch of his magic. He didn't relent. Grabbing her other hand he pulled her arms away from her body to what must have been a painful degree.

Pinned to the rock by Sans' magically augmented strength Frisk struggled feebly for a moment, then realized she couldn't escape. Her breathing was tight with pain, which Sans couldn't help but relish.

 _ **"what. did. you. just. say."**_ Sans' voice was flat as a tombstone, hollow as an empty grave.

Frisk was staring at him with horror that was one part present and two parts remembered. Good. So she remembered the Judgement Hall. He felt more than saw the bones that had begun swirling around behind him in a mandala of promised suffering.

"You won't like it." Frisk admitted, her eyes pinned on the bones, as if preparing to dodge at a moment's notice. Sans noticed that her soul, pure blood red, had manifested over her chest and beat with a frantic, uneven rhythm.

 _'Ratatatat tat. tat tat tat. Ratatatat tat. tat tat tat.'_ It was like music to him.

 _ **"too late for that, kiddo."**_ It was true, he knew where this was going. He'd known for a long time, but the knowledge was buried in his past selves.

"There was- AGH!- a man!" Frisk cried out as Sans increased the pressure on her joints.

 _ **"i know."**_

Frisk's watering eyes widened a little at the revelation.

" _ **why."**_

"Because.."

 _ **"tell me."**_

"Because I-..."

 _ **"..."**_

"I wanted to stay here with you. With all of you." Frisk's voice was barely a whimper now and there were tears streaming from her eyes. Still, her full lips were curved up in a sad smile.

Disgusted, Sans banished his magic and turned away, letting the girl fall to her knees and cough as her muscles spasmed at the sudden release. Still, she looked up at him with eyes full of love, not LOVE.

"I - hack- only wanted to stay here. But everything was always the same. It was so boring and then one day I - cough - met him." Frisk struggled to get the words out, frightened into submission.

Sans crouched down in front of her, his heavy frame looming and his eyesockets devoid of light.

"gaster." Sans supplied.

"Yes." Frisk answered. "But I had to give him something in return for him changing things around."

Sans could only stare at her in horror, teeth bared.

"He wanted the other human souls."


	4. Chapter 4- WHATEVER CAN BURN WILL

**Sans swears alot when he's drunk. Also, a great song to accompany this chapter would be:**

 **www youtube com / watch?v=cQKGUgOfD8U**

 **or just:** 【VOCALOID Original】ECHO【Gumi English 】 **since FF doesn't seem to like URLS  
**

 **Also I write Mettaton as a guy. So sue me.**

* * *

Sans made a show of returning Frisk to Papyrus and Toriel as they met up at the entrance to the darkest caverns of Waterfall, the ones lit only by mushrooms and lanterns. This time, however, the whole area was bright as day, giving the impression of the inside of a watery disco ball. Sans really shouldn't have been surprised.

"see ya' around, kiddo." Sans mustered up his best grin and even pat Frisk once on the head to assure the others that everything had been fine. He even took the time to apologize to Papyrus about how he'd acted before. Told him that all he wanted was for him to be happy. The lie felt dirty on his teeth.

Frisk stared at him with what seemed to be a mixture of longing and residual fear.

"I'M GLAD YOU'VE COME AROUND. TO MY NEW GIRLFRIEND!" Papyrus chattered happily and Sans tried to be happy for him. His brother really was too pure for this world. "IF ONLY YOU HAD TAKEN A MOMENT EARLIER... TO GET TO KNOW HER. YOU ARE VERY FUNNY, SANS."

"i'll take that as a... condiment?" Sans winked, feeling his mask clicking back into place and drawing comfort from it.

"AAAAAAAAAAH!" Papyrus shouted, shaking a few stalagtites from the roof through sheer sonic force.

Frisk giggled a little, watching Toriel's fur stand on edge at the noise.

Turning his back on the trio as they gawked at the spectacular light show in the next room, Sans felt his shoulders droop and his stomach growl. He felt absolutely exhausted.

.

After quickly detouring into his lab to update his notes in detail, Sans found himself sitting at his regular stool in Grillby's, ketchup bottle in hand.

There was simply too much to process, between the rapidly emerging memories from his past selves and the danger Papyrus was in every moment that Frisk drew breath.

And, how could he forget, the _fucking stupid_ deal that human _idiot_ had made to re-write time with an omnipresent, nearly omniscient extradimensional entity with the power to influence the threads of space-time like he was knitting a scarf. And what had she given him? Oh. Only _six fucking human souls._

 _fuck._

He had to do something. Had to think his way out of it. He took a long swig of condiment and felt everything become comfortably numb. Sans distantly realized that doing this would in no way help his mental processes, but he couldn't bring himself to face what was happening in the glaring light of sobriety.

...

Ring...

Ring...

Sans jolted awake at the sound of his cell, immediately regretting it as his skull ached with such ferocity he thought his cranial sutures were coming undone.

"agh... hello?" Sans asked into the reciever, feeling disoriented. For a moment he feared that the human might have RESET again, but then he took a look at his surroundings and calmed down. Not timesickness. Just a hangover. He was currently wedged onto the bench of one of the tables in Grillby's. It was dark and empty in the bar and someone had given him a blanket. Huh.

"HELLO BROTHER! THIS IS THE GREAT PAPYRUS!" Sans' winced sharply as needles of pain lanced him. He quickly thumbed down the cell's volume.

"uh, hey paps. what's up?" He asked, still holding the phone at arm's length.

"HAVE YOU. SEEN UNDYNE LATELY?" Papyrus blared through the earpiece. Now that Sans was more conscious, however, he was able to detect a tone of worry in his brother's voice.

Now that he thought about it, it was strange that they hadn't encountered the leader of the royal guard yet. She should have been tracking them ever since Papyrus failed to capture the human (one way or another).

"no. sorry. anything i can do to help?" Asked Sans.

There was a long, ominous pause on the line.

"WOULD YOU MIND. COMING OVER TO UNDYNE'S HOUSE? QUICKLY?" Yep. Papyrus was definitely on edge about something.

"sure thing paps. hold tight, okay?" Sans had already squeezed out from between the booth and the table as he heard Papyrus' brave "OKAY." followed by the call going dead. He did his best to fold up the blanket neatly but it just turned into more of a snarled mess. He'd apologize to Grillbz later.

Steeling himself, Sans walked through the shortcut beside the jukebox...

... and emerged a little ways outside Undyne's house. Red and orange light danced across the cavern's vaulted ceiling and Sans could smell smoke. Unsurprised and unsettled, he rounded a corner to find Undyne's house already on fire. Which was odd considering Papyrus had said that they hadn't even encountered her yet. It least this would offer a distraction from his hangover.

If the fire hadn't been caused by cooking antics, then what?

Sans sauntered up to the group of figures who were standing in front of the blazing house. He noted that in addition to Frisk, Papyrus and Toriel, Napstablook, Alphys and Mettaton (already in his EX form) were in evidence.

As usual, Frisk was the first to notice his approach and Sans was careful to keep his face perfectly neutral in response to her nervous smile. Did she really think there could ever be anything between them? That there ever could have been?

Maybe once he'd felt compassion towards her, but she'd been a child then. She also hadn't been a genocidal maniac.

She seemed to sense his thoughts and her eyes dropped to the floor.

Why did he feel a pang of guilt?

"Papyrus, Darling, I'm afraid that's just not how fire is supposed to work." Mettaton had just finished saying in his sensual, robotic voice, one leg poised high above his head and his left hand making a peace-sign seemingly of its own accord.

Papyrus was staring at the burning house indignantly but then noticed Frisk's distraction and turned to see Sans approaching.

"YOU GOT HERE. FAST?" Papyrus closed the distance in one leap and pulled Sans to his chest in a bear hug. Sans was glad to see he'd gotten over their earlier fight so easily. Then again, this was Papyrus after all.

"you're the best, bro." Sans dodged Papyrus' implied question and returned the hug. Papyrus had certainly gotten much stronger with Undyne's training to be able to lift him so easily off the ground. "how can i help?"

"Well- uh... the house is... as you can- uh, see, on fire." Alphys slouched up to the brothers, looking up at them uncertainly. Sans briefly wondered if all monsters seemed so short from Papyrus' perspective. "But it's also- um. Not... on fire?" Alphys muttered, grabbing her tail between her claws. She seemed distressed. Well, more than usual, that is.

Sans gave his brother a loving tap to let him down before continuing the conversation. He didn't like talking down to monsters. "whada'ya mean?" He asked.

Actually, taking a closer look at it, Alphys was right. Only half the house was actually burning. There were patches where no mater how ferocious the inferno, the flames would not go. It was making Sans feel distressed as well.

"WE THOUGHT THAT. SINCE YOU AND DR. ALPHYS ARE GOOD WITH SCIENCY THINGS. THAT YOU COULD HELP." Papyrus had his puzzle-solving expression on. Which meant he'd just drawn stern eyebrows on his forehead with a Sharpie marker.

Just one enigma piled on top of all the rest. Sure. It wasn't like he was already drowning in quantum-mechanical shit already.

"has anyone tried to. i dunno, knock?" Sans asked, grinning. He was met by three stares of disbelief, one tearful one, one dramatic one and one determined one.

"nooooooooooo..." Napstablook called quietly as Sans smirked and started to walk up to the house's flaming front door.

Sans could feel the heat of the flames licking at him with an almost physical strength as he approached, even if he couldn't _actually_ sense their warmth. It made his bones creak.

"knock knock." He said, rapping on the door and feeling his knuckles crisp a little.

He was met by a roaring silence that implied that only fire lived here now, and yet it didn't at the same time. Had he ever mentioned how much he _hated_ quantum mechanical shit?

...

Sans was half way to knocking again when he got his reply

.{W-H-O-'-S- -T-H-E-R-E-?}.

With a snap like long fingers breaking the flames froze in place. Startled, Sans tried to phase away from the house with magic but found that he suddenly couldn't. He fell on his ass instead and scrambled backwards without even a thought for dignity.

He looked up at the other monsters, ready to feel embarrassed but found that they'd frozen in place as well. Only Frisk blinked, concerned.

This time Sans did accept Frisk's offer to help him stand, and he shakily brushed the dirt off the back of his hoodie and pants.

"What happened?" Frisk asked, waving her hand in front of Mettaton's face which was comically frozen half-way between sticking his tongue out and winking.

"not sure." Sans answered honestly for once. He tried to keep his hand from rattling as he wiped off his sweating skull. Internally, he tried to reach for his magic again and again and failed each time.

Nothing. If the human figured out he was defenseless, he was as good as dust.

He forced his cheekbones back into a semi-cheerful arrangement and gave a dry chuckle.

"maybe they were scared... _stiff?"_

Amusement danced in Frisk's eyes at the terrible pun, but her concern for her friends stopped her from laughing.

"what. not funny? maybe this one'll _draw_ you in?" Sans let his mask of humor conceal his inner terror as he tugged the Sharpie out of Papyrus' glove and set to work on drawing funny things on everyone's faces. He could see that Frisk was now struggling to contain her amusement.

Good. If she was laughing, she wouldn't be murdering.

 _A rogue memory flitted through Sans' mind of a little girl with a red ribbon in her hair and a toy knife. She'd been laughing hysterically as a vegetoid cut her down._

Distracted, San's arm clenched and a kawaii eyelash he'd been drawing on Alphys' turned into a long streak up her crest.

"eheh." Sans coughed, hoping Frisk wouldn't read too much into that.

"Sans. Don't worry about me. You don't have to be brave for my benefit."

Sans turned around slowly to meet Frisk's level gaze. She seemed genuinely concerned. Her dark, soulful eyes really were beautiful in that moment, and the way her hands clutched uncertainly at the hems of her sleeves was tying him in knots.

 _are these more memories?_ He asked himself, wondering why he couldn't keep himself together in front of one human child. Of course, she wasn't a child any longer. And she was Frisk.

Frisk, who drew Sans into a hug out of nowhere, pulling him in tightly and pressing herself into his soft tum. He froze in fear and... something more?

Frisk, who then with a mischievous sparkle in her eye took the marker from him and drew a curly, dastardly mustache on his maxilla. "So no one will suspect you." She laughed, winking.

Frisk, who took his hand determinedly in hers and guided them both to the now-yawning-open front door of Undyne's half-burnt and blackened house.

Sans was filled with trepidation. But he walked forwards anyways.

.

.

The interior of the house was... Sans struggled to find a word to describe it. The angles felt off slightly, like a long tunnel that veers slightly in one direction but you can't see the end yet. Like catching your reflection as you stand between two mirrors and thinking that one of those infinite 'yous' had just winked.

Frisk's grip tightened on his hand. At least he wasn't the only one feeling it.

Parts of the interior were pristine while other parts were melted and black. It hurt to look too closely, but Sans made himself. An energy spear flickered in an out of existence, wedged in a table that was and was not cracked in half. The porcelain sink had exploded from the heat of the blaze and some of the shards had landed in the unburnt areas. Those seemed to be shivering.

Sans watched in fascination at the moustache Frisk had just drawn on him peeled off and floated away.

Frisk, brave soul that she was, approached the piano and tried to play the tune from the Waterfall Statue's music box. The notes fell flat in the dead air.

Sans had just been about to propose leaving when the front door slammed shut, startling them so badly Frisk nearly jumped out of her skin. Sans just jumped.

They shared a brief, terrified glance and then rushed to the window Papyrus had always leapt through. It was hard as granite. Now, either Papyrus was really downplaying his strength, or something didn't want them to leave.

Sans stopped pulling at the lintel when Frisk put her hand on his, shaking her head. Her long-ish hair swayed in defeat. She walked to the center of the room with her shoulders back and her head high, though her knees looked wobbly.

"G-gaster?" She asked the hostile air. It was utterly silent but for her breathing.

There was a long moment in which nothing happened. Frisk looked at him nervously and then jolted again when something caught her eye.

The door leading to Undyne's bedroom was open. As if it always had been that way and they just hadn't noticed before.

"we're gonna have such a bad-" Sans began but Frisk put a finger to his teeth, a warning look in her eyes that read ' _you'd better not say what I think you're about to say_ '. If Sans had had access to his powers he might have fought her on it, but as he tried for the hundredth time to reach them there was still _nothing_. He shrugged as if conceding a point and then walked after her into the darkness beyond the doorway.

* * *

.

 **Then next chapter will be coming out tomorrow morning. Trust me. It's a doozy. O_O**


	5. Chapter 5- BUT THEY REFUSED

**An early title for this chapter was: In which Sweet CinnaBun Papyrus is too Pure for this Fic.**

 **SERIOUSLY. Buckle up for feels.**

 **Also, I tried to re-create the feeling of an Encounter and I hope you guys like how it turned out.**

 **WARNINGS: Some implied gore, mention of suicide, emotional trauma on the part of the reader, character death.**

* * *

CHAPTER 5- BUT THEY REFUSED.

It wasn't just black in here, it was **black**. As in so black Sans thought he could almost see colors in it because his eyesockets just didn't know how to process it. There was a low humming noise coming from everywhere at once and the only point of reference was the white square of doorway behind them and Frisk.

Sans grabbed her hand in what he hoped was a reassuring way (It reassured him, at least). And wondered if it was too late to call a T.O. so he could go get some ketchup. Hell, he'd accept mayonnaise at this point.

Frisk gasped as her soul appeared in the middle of her chest, signalling an encounter had begun. She and Sans looked around wildly but they could see no enemy. Nothing but the empty, maddening black. Sans was sure he could see symbols now in the void, vibrating and oscillating like the needle of a seismograph as the world split in half.

"Gaster?" Frisk asked again and the darkness seemed to tense up at the word.

Sans briefly considered cracking a joke and asking "What's black and black and black all over?" But then he remembered Gaster didn't like jokes.

 _no._

 _wait._

Gaster _did_ like jokes, Sans thought. There was something about that memory that recoiled from him. He knew it was true, but for some reason his mind didn't want him to know that. Very peculiar. Maybe there was more to his memories surrounding the Good Doctor than he'd originally thought.

The darkness seemed upset at his line of reasoning and the humming got louder. The door slammed closed behind them, cutting out all light from the world but for the ruby glow of Frisk's soul. Finally good and frightened, she tried to hide herself in his broad chest, quaking and shaking her head.

"hey, uh. there there." Sans pet her hair uncertainly, keeping both eyesockets open for any sign of an attack. Again he tried to summon his powers. Again nothing.

Something had materialized in the darkness over Frisk's shoulder but it wasn't what Sans had expected. It was Undyne in her Undying form except her armor was missing huge, discreet chunks like something had simply done away with those sections of reality. Her right arm was missing. She looked up at Sans holding Frisk to his chest with abject horror and confusion.

Undyne didn't even have a moment to vocalize her thoughts before she crumbled into dust.

.

.

.{H-A- -H-A- -H-A-}.

The darkness chuckled like a scrambled dial tone. The background noise stepped up again, like putting your ear to a beehive. That feeling of cold hands on his shoulderblades descended again on Sans. It was behind him.

He _really_ didn't want to look.

He _really, really_ wished he had some way to defend himself.

Slowly, Sans turned his head. He could hear the grinding of his neck bones as he did so, despite the fact that the buzzing\humming\screaming was deafening now.

 _Dr. W. D. Gaster_.

Sans looked up from the thin, boney fingers that rested on his shoulder, paused briefly at the holes gouged into the palms, up the long, long arms and finally to the white face he'd always known would be there. It looked disapproving. And sad. And so incredibly lonely.

Sans remembered that look back from his days as Gaster's assistant researcher into the properties of souls and determination and their utility in powering the CORE. He'd always looked up to Gaster, even as he'd watched him kill himself for the sake of monsterkind.

The cracks in Gaster's bone-white face ground together as it contorted in sudden anger and his hands clenched so tight into Sans he felt his soul splinter.

"aaaaaaaaaagh!" Sans cried as the Doctor picked him up and threw him into the darkness like a marionette. Sans clawed against the smooth, insubstantial ground (if it even was ground) as he felt his legs dangle out into a bottomless void as the plane of "floor" ended in a sheer drop.

His fingerbones made a screeching noise as he tried to find some purchase on the slick ground, but without his magic he was too heavy. too weak.

He watched helplessly as Frisk leapt and dodged Gaster's white, claw-like hands as he tried to pin her. She wasn't fighting back.

Sans opened his jaw to shout at her to FIGHT, to tell her that MERCY was as good as useless here, but his conscience stopped him. Hadn't he spent the last eternity telling her not to do _exactly that?_

 _but this is different._ He rationalized, scrabbling once again as he started to lose his grip on the tenuous ledge.

Frisk flipped nimbly as Gaster unleashed a hell of bullets in her direction, dodging every one. But her luck couldn't last forever.

 _is it different? frisk'd been in situations before where outright mercy wasn't the answer. if anyone could find a way, it was her_.

A cut-off scream split the void as one of Gaster's vicious attacks connected, sending Frisk flying backwards until she landed with an awkward half roll. Her soul's light was only half as bright as it had been in the beginning. Frisk looked at it's diminished glow and only had the time to register alarm before the next wave of attacks commenced.

"no!" Sans shouted. Trying to lift one leg up and hook it onto the ledge. He nearly slipped a few times but finally the protruding calcaneus bone in his heel caught and gave him enough leverage to pull himself up, panting and out of breath.

Frisk dodged determinedly and stuck close to the ground as Gaster's cruel fingers swept through the air where her soul had just been. Then he reversed his attack and Frisk was forced to evade the unexpected angles his hands made in the air.

As Gaster paused briefly, Frisk tried to access her pockets to get at her healing items but something was stopping her. She gasped as Gaster interrupted her turn with a lance-like thrust of his fingers and sent her flying backwards again.

Sans ran, hoping he wasn't already too late.

 _MERCY isn't the answer here._

He didn't even try to access his magic.

Out of the corner of his field of vision, Sans saw Gaster summon the six human children's souls and let them hover just above his arms. Whereas before the Doctor had seemed cold and vengeful, he now seemed glad. Excited even.

 _oh god. he's going to take her_ _soul._

Gaster's already-cracked face began to riddle itself with hairline fractures as space seemed to fold in on itself. The distance between Sans and Frisk seemed to telescope and foreshorten simultaneously, so when Sans jumped he wasn't even sure if he was even close to the mark.

The digits of Gaster's hands twitched like snakes in a pot as his face cracked in half, revealing a new face, but Sans didn't get a chance to look at it. He was blinded by the horrible light that was building between the holes of Gaster's hands, clasped together.

Sans' fingertips touched Frisks as he launched himself between her and the unavoidable attack.

 _not MERCY,_ he thought, _SACRIFICE._

Gaster's beam attack, empowered by the six human souls hit Sans in the back like a freight train made of lightning. It tore through him with such utter, reality-defying precision that Sans could actually _feel_ his soul being ripped from his body.

The last thing he saw was Frisk staring up at him, surprised. There was a foot-wide hole in her chest and her soul had split with a sad, quiet sound that echoed in his skull. He hadn't been able to save her.

.

.

.

Papyrus blinked. The house was no longer on fire, which was good. But his brother was also no longer there, which was not good. Papyrus decided that this situation fell under the category of: Definitely quite bad.

"My Child!" Toriel shouted, causing Papyrus to turn around suddenly.

Toriel was looking around frantically, which would have been more worrying if she wasn't sporting a comically drawn-on monocle. But now that he looked around more, Frisk was definitely also missing which moved things from "Definitely quite bad" to "Buckle up, everyone".

"...ooooooo." Napstablook finished their lamentations (when had they stopped? Papyrus couldn't remember).

Then Alphys started snickering at the butt drawn on Mettaton's cheek and quickly everyone was in quite a tizzy. Papyrus quickly hid the incriminating Sharpie in a fold of his armor.

"EVERYBODY STOP!" Papyrus shouted, waving his arms. Everyone did, indeed, stop. Which he really hadn't been expecting and so he got nervous. Something definitely felt very wrong, though. Wrong in a way that felt slightly familiar but he couldn't quite put his finger-bone on.

Then the front door of Undyne's house opened with a loud creak that drew everybody's eyes. It was **dark** inside, Papyrus realized. For a long moment nothing moved, but eventually something emerged.

It was strangely hard to see, blurred around the edges as if someone had rubbed their finger there.

As it got closer, Papyrus bleached in shock. Toriel made a sort of wailing noise and the other three remained completely silent.

It was Sans but... but... grey? And he was holding... _something red._

The red was dripping down San's grey hoodie over his grey bones and onto his grey slippers. His expression seemed lost and confused, even when Papyrus put a hand on his shoulder to stop him.

Sans resisted stopping for a moment, as if he didn't understand why but eventually he stopped pushing. His eyes were immeasurably more hollow than usual as he looked up at Papyrus' face.

"s-sorry." Was all Sans said before he crumbled into dust, leaving Frisk's corpse at Papyrus' feet.

.

.

Sans beat at the walls of his prison as he watched these events take place from a space that both was and wasn't and never would be. He screamed his non-voice raw as he watched Papyrus cry and gather up his hoodie, which had at least regained its normal blue coloring as the last remnants of Sans' consciousness had left his body. Probably because that hoodie had never been his in the first place.

The other monsters huddled close in sympathetic grief as Sans watched, struggling with all his feeble strength against the white hand that held his soul. Futile. Useless. Pathetic.

Sans shifted his field of view to encompass Gaster's other hand, where Frisk's soul still sat in two pieces. In his current, disembodied state he could sense her hurt, her regret and her love for the monsters whose emotional torture she was being made to watch.

Drawing his attention away from the agony of grief that his existence had become, Sans sensed that his soul had split as well. He should be long gone by now. Why was Gaster expending such immense power to keep him around? Was he just _that_ cruel? Did he want him to watch as... Papyrus... hands covered in _his_ dust...

Sans' soul burned.

Burned.

 **BURNED.**

With a strength beyond any his magic had ever allowed him, _Sans refused._

This is not how this would end. Sans had never known pain like this. Never. Not even when Frisk's knife had split that Sans in the Judgement Hall who had finally drawn the short straw.

Sans felt himself tearing at the seams as he _**pushed**_ against Gaster's hold on him. Against the might of six human souls he struggled. It felt useless at first, but then he began to move.

W. D. Gaster's new, shadowed face emanated concern. Confusion.

 _ **good.**_

Then, even as San's pushed, he _**pulled**_ and he saw Frisk's shattered soul start moving towards him. It seemed that she also refused.

Gaster was becoming alarmed, and pressed into Sans with the weight of his god-like power. He was just a lowly boss-monster after all. Not even a human. But still, _Sans refused._

The pain of his brother, his sweet baby brother who Sans had only ever wanted to protect drove him on through the burning.

On.

And on.

And on through the burning.

Finally, after all sense of time and self had nearly ceased to exist, the broken halves of Sans' soul touched Frisk's and together...

...each half found its counterpart in the other...

... _and they refused._

* * *

 _._

 _._

 _._

 _._

 _._

 _._

 _._

 ** _okay whew I can breathe now._**

 ** _Writing that was. Really hard. ;n; I think I'm going to go lay down now. But oh, don't think for a second I'm done with your feels yet._**

 ** _Next Chapter Coming tomorrow (Sunday)!_**


	6. Chapter 6- UNDERFELL PT1

**Gonna lighten things up here for a bit because that last chapter was emotionally exhausting. Also, now we get into the meat of this fic!**

 **P.S. The designs of the characters in Underfell are not mine and can be found in the 'underfell' blog on Tumblr if you're curious. They are all precious, evil babies that deserve some tough love. Especially Chillby.**

CHAPTER 6- UNDERFELL PT.1

There was a strange song playing in the background as Sans began to regain consciousness. It sounded like a choir of people humming discordantly but somehow managed to be mellow and relaxing, if a little quirky.

The little lights in Sans' eyesockets blinked a few times before focusing.

Frisk lay on the navy-colored dirt beside him, just beginning to stir as well. Mustering his strength, Sans sat up in a body that felt ungainly to him. Why did he feel so unusual? He couldn't remember, but the term: 'out of body experience' wound its way to the forefront of his mind. Had he died again? The thought flitted away before he could fully process it.

Looking around, Sans was surprised to discover that he and the human had collapsed smack-dab in the middle of Temmie village. But _which_ Temmie village? When? _**Which**_ _ **when**_? God, he hated time travel.

"HoI hOi!" One of the Temmies scurried over and pushed her round head right into Sans' personal space. "Not sEe u com In!" It yapped. "Want buy TeM fLakes?"

Sans didn't have time for this right now. Gently, he put his palm to the top of the small Tem's head and picked her up like a basketball. Slightly less gently, he dunked her into a wide crack in the cave wall.

Frisk giggled at his antics, having apparently woken up behind him.

She blinked blearily and rubbed her forearm across her eyes. She looked about as haggard as Sans felt right about now, and her brow was creased in thought. As if she were trying to remember something too. Now _that_ was unusual. Frisk _never_ forgot timelines.

"When are we?" She asked, still rubbing her left eye like it was bothering her. Sans took a deep breath, feeling deeply unsettled. Something had happened. Something really, _really_ bad. He could feel it in his bones and it made him angry that he couldn't remember.

Sans helped Frisk to stand and wondered at the fact that he didn't feel uncomfortable in her presence despite still him still retaining the memories of those past time lines where they'd... had differences in opinion. Mostly regarding murder.

He had been about to reply when Frisk dropped her hand and stared at him full in the face. With one regular, dark eye... and the other a burning electric blue.

It felt like a dam breaking in his mind.

The argument with Papyrus, the memories of trying and failing to protect the previous children. Confronting frisk, learning of her deal with Gaster, getting drunk. Hugging Papyrus, entering the burning house, Gaster. Fear, burning, _watching his brother holding his dust-covered hoodie to his chest_. _**refusing**_ **.**

It felt like falling through ice into frozen water. That had happened. To him. To Papyrus. _His Papyrus_. Sans heard someone cry out as he clutched his skull between his hands, falling back to his knees. It was only as he felt Frisk's arms around him, comforting him and getting the fur lining of his hoodie soggy with tears that he realized the sound had come from him.

New body, new hoodie, he supposed.

He felt claustrophobic, but not from Frisk's presence. He felt stifled by reality itself, and by the presence he knew was surely watching.

"He CaN't C u heRe." Came a mewling voice. San's vision was swimming with radioactive-blue tears as he opened his eyesockets to find a Temmie wearing a college graduation-cap staring up at him. There was more intelligence behind those beady eyes than he'd ever seen from a Temmie.

"Who? Gaster?" Frisk asked, turning to face her so as not to be rude. Sans resented the loss of her comforting embrace momentarily.

The shrewd-looking BussinessTem's fur stood on end at the mention of the name but she nodded briskly.

"TeM VilLagE proTeCted." She continued. At Sans and Frisk's puzzled stares the Temmie simply gestured _up_ cryptically. Sans had always known Temmie village was a universal constant. Always unchanging and like an ant-hill of shortcuts, most of them nonsensical and some of them leading nowhere at all. He'd always avoided the place for that reason.

But now a thought struck him: Maybe those empty paths had gone somewhere? Maybe they just hadn't led anywhere he could go. Now, looking around the room, Sans could see the trails leading off through time and space. Some were obvious, but others so craftily hidden or so small he'd never noticed them before. Those, he could see now, led to completely different universes.

Frisk stiffened beside him suddenly, pulling Sans out of his revelation.

"I... can _see_ them." Frisk whispered, her eyes as wide as they would go.

Sans didn't have to ask what it was she could see as he watched her left eye glow with his magic. She could see the shortcuts too. How many of them she could find and whether or not she could access them had yet to be determined.

"buT... CaN't steY 4EvEr." The Temmie didn't seem to be following their whispered exchange and was going right ahead with her monologue. "U tWo GotTa keeP mOvIN."

"Where?" Frisk asked, taking the reins of the situation. Sans still didn't trust himself to speak. He didn't want to even _think_ in case he thought about... Sans derailed that train of thought hastily.

Temmie looked at one of the closest shortcuts. It didn't lead anywhere in this universe.

"Okay." Frisk said determinedly, delicately helping Sans to his feet again. He wondered at how she could manage to be so calm about all this. About leaving their _fucking universe_ to escape the void-crazed, god-like monstrosity that had been Sans' former boss and-

Again his mind recoiled from that line of thought.

Weird. But there was no point dwelling on it.

Stepping into the shortcut was easy as ever, just like taking a step. There was a slight squeezing sensation as they moved between the folds of time, a moment of weightlessness

and then a strong gust of wind as they emerged into the Snowdin forests right outside the Ruins Door.

It was night out, Sans thought for a moment. Scattered memories of living on the Surface tried to help him understand the unusual darkness of the forest, but that was nonsensical. There was no night underground.

Frisk coughed beside him and Sans turned to find her shivering violently. It must be very, very cold. Quickly, he removed his thick hoodie and helped her into it.

"T-thanks" She chattered, zipping it up and burying her nose in the fluffy hood.

"no problem, bucko." Sans felt his grin reach his eyesockets despite the bizarre situation. She looked cute in his hoodie.

"I wonder what's different about this universe." She pondered, her voice muffled by the thick fabric.

"guess we'll see, huh?" He replied, taking her under his arm protectively.

...

After a long, cold(for Frisk at least) slog through the snow Sans was relieved to finally see the cozy glow of Snowdin up ahead. He had been perturbed by the lack of puzzles on their way through the mountains(not even a single trap spaghetti!), but Sans supposed that anything was fair game now in terms of timeline fuckery. God, he needed a drink.

"keep yer hood up, kid." Sans whispered to Frisk as they entered the town proper. The monsters were looking at them suspiciously and without even a hint of their usual kindness. Everyone was dressed in menacing blacks and reds and golds.

It seemed they'd come to the wrong neighborhood.

Frisk nodded, sensing the other monsters' hostility and drew her hood down over her face until only the barest glimmer of her blue eye was visible in the shadows.

Deciding it was better than breaking into his alternate self's home for shelter, Sans steered them both towards Grillby- er- Chillby's bar. So that was how this universe was going to be. _Great._

The air in the dive was devoid of grease, making Sans immediately decide he wanted nothing more to do with this backwards universe. He took the bar stool that would have been his usual one and was interested to discover that the cushion had the same, squished feeling that his own had. Huh. Frisk took the stool beside him, rubbing her arms through the hoodie to get some warmth back into them.

"So what's the plan?" Frisk asked, ready to take on the next challenge even if she was practically dead on her feet from exhaustion.

"that's a good question." Sans said quietly, absently peeling back a corner of the pristine varnish on the bar-top with his thumb-bone. "first. we need to undo the mess you made by getting the other souls back where they belong."

Frisk wilted a little, accepting the blame entirely.

"then we need to get back to our own universe and timeline, which'll be the tricky bit."

"How will we even _find_ them again? I can see all these paths now... but it all seems like such a mess." Frisk gestured at the gaping holes in space-time throughout the bar that only they could see.

"messes are my speciality," Sans winked. "we'll find a way. after all, my little bro needs me, y'know? he gets real cranky without his bedtime story." He felt his grin slipping again but couldn't bring himself to fix it. Besides, there was no point hiding his emotions around Frisk anymore.

But now it seemed they had another problem.

Sans could feel the dour glares of the other patrons in the bar on their backs as they sat there. One of the Guard Dogs, a Greater-sized Rottweiler even let out a low rumble. Feeling the tension, Sans noticed that Frisk's hands had begun trembling as she gripped his hoodie.

 _if that's how they want to play, then fine._

Giving Frisk's trembling fingers a reassuring squeeze, Sans turned around in his stool to face the rest of the bar. Yep. Everyone was definitely riled up about them being there.

" _ **what.**_ " He asked the room at large, cracking his knuckles for effect. " _ **you guys got a problem?**_ " Sans let his grin shift into something ugly as he stoked the flames of his newly-augmented magic, letting it course through his body like an electric charge.

Then, on his chest, he was shocked to see his soul manifest.

Now he understood how they'd escaped Gaster. Why Sans felt so much more powerful and why Frisk's eye had turned blue. The soul that hovered right above his solar plexus consisted of two different halves: The left side white and the right side a deep, crimson red. He had part of a _human soul_ inside him. Frisk's startled gasp beside him made her thoughts on the situation clear.

The atmosphere in the bar changed instantly.

Lesser-Rottweiler ducked under his table with a little whine, Dogamy and Dogaressa huddled together for protection and even Doggo went perfectly still.

Sans smirked at their quick submission, even if something about it unsettled him.

"bunch'a creeps" Sans muttered as he let his now-burning eye sweep over the room one last time before settling back onto his stool. The room was silent as Chillby brought out two servings of salad and a plastic squeeze-bottle of mustard that he set between them with a cold stare. Sans looked down at the vegetables in disgust.

"What's wrong with them all?" Frisk asked quietly, still obviously shaking from discovering that they'd effectively traded parts of their souls. However, it had probably been ages since she'd eaten so she dove right into the salad. "Why're they -munch munch- so scared of -munch- you?"

Sans pushed the salad away and went for the mustard. Not his favorite beverage but it'd have to do. "i get the feelin' that people aren't so nice in this universe. if that's the case, i wouldn't put it past alternate me to be the worst a' the bunch." San's forehead crinkled at the admission. "eat quick, kid. we need 'ta find somewhere safe to sleep."

"Safe from -munch- who? Ga-" Frisk stopped herself before uttering the name. She didn't want to attract his attention to them, superstitious as that was. "- _Him?_ "

The grin on Sans' face faltered.

"nah. safe from _me._ "

.

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* * *

The Alpha Universe Papyrus knelt where he'd been kneeling for hours now, with no intention of moving. The ground around him had taken on an orange-tinted glow from all the orange-tinted tears that had been falling on it. Papyrus shuddered as another wave of grief broke over him and his fingers tightened further on the dust-covered hoodie he was clutching to his chest.

"Shouldn't we do something for the poor dear?" Mettaton asked from where he was standing with the others some distance away. Papyrus could hear them talking about him clearly, but he just couldn't bring himself to move. He never wanted to move again. He'd just turn to stone because then at least he would have to feel... _this._

He didn't look up as the tall, white shape of Toriel approached and then knelt beside him. She placed a loving paw on his back and made reassuring, motherly noises. It felt kind of nice.

"Do you need anything?" She asked softly, her voice full of concern.

Papyrus shook his head and stared straight ahead, not wanting to break into tears again. Not in front of everyone.

"Okay. That's okay. Dr. Alphys is looking into the anomaly that caused the fire in the first place. We are going to figure out what happened." Toriel's heavy paw felt comforting on Papyrus' spine and he felt guilty that it was _him_ being comforted right now. That there was nothing anyone could do to comfort his brother. Or the human.

"I-I f-f-found something!" Alphys voice broke the leaden quiet of the cavern as she rushed out of the house like it was still on fire. "H-ere! L-look!"

The little yellow-scaled monster practically slid to a stop in front of Papyrus, causing him to forget his pain long enough to be curious. She was cradling a little glass vial very carefully between her claws, holding it so that the faint, red light it emitted could be seen by everyone.

"Is that a... piece of the child's soul?" Toriel asked, her voice full of awe and disbelief as she looked at the tiny splinter of red.

"M-more than that!" Alphys seemed buzzing with frantic energy. "I r-ran some... t-tests. There are... t-traces of Sans' s-soul in there too!"

Papyrus couldn't disguise the sudden hope that welled up from his empty chest and onto his face. He couldn't smile, not right now. But he wanted to. He held Sans' hoodie closer to him, willing his brother to come back.

"But how is that possible, Alphys Darling?" Mettaton and Blookie were both crowding around now as well.

"I-I'm... not... sure. S-since they're both... g-gone... it doesn't make sense t-that any p-piece of their s-souls would remain intact. I... d-don't want t-to get anyone's hopes up..."

"BUT IT'S SOMETHING, RIGHT?" Papyrus asked, speaking for the first time since his brother had dusted. His voice sounded creaky.

Alphys looked like she really didn't want to give him any illusions about his brother coming back. Something inside Papyrus told him that she'd made that mistake before, but he couldn't place the source of the memory.

"I-it's r-r-eally unlikely... s-so... p-please don't be m-mad if it t-turns out... t-to be nothing, okay?" Alphys muttered.

Papyrus nodded, accepting.

"TELL ME HOW I CAN HELP." Papyrus said, standing back up to his full height. He contemplated the hoodie in his arms for a moment, then put it on. It was very short and baggy on his frame and it smelled like grease, but it felt like Sans. It gave him the determination to continue on.

.

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* * *

 **So just to be clear, Frisk and Sans didn't do a full 'fusion' as some of you had been expecting, though That AU is definitely still on the table considering the nature of this tale. ;P Instead, Frisk had gained the ability to access a small fraction of Sans' skills which may or may not be limited to seeing shortcuts. Sans arguably got the better end of the soul-stick as he now has increased magical potency, though perhaps that will come at a cost? We shall see!**

 **Next Chapter up tomorrow morning!**


	7. Chapter 7- UNDERFELL PT2

**Thank you everyone for your continued support! If you have any specific AUs you would like Sans and Frisk to visit, please leave a review! :)**

 **I might have people vote on the next AU to travel to if I get lots of suggestions. Current suggestions: UnderSwap, Fusion, Bromalgamate(guys why would you put them through that? ;o;).**

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* * *

WHATEVER CAN HAPPEN WILL

CHAPTER 7- UNDERFELL PT.2

"Tro lo lo~..." The River Person cooed as their boat continued to speed through the underground tunnel. It seemed this version of the ferry-driver had a sick sense of humor when it came to "fast travel", considering they'd been at it for nearly six hours.

After some initial confusion and harsh words, Sans and Frisk had finally acquiesced to their fate and laid down in the boat to get some much-needed shut-eye.

Sans watched as Frisk dozed, feeling like a bit of a creep but not wanting to wake her before he had to. He'd grown accustomed to living on not enough sleep but she was still a growing girl. He grinned as Frisk's faced scrunched up at something in her dream and her fingers twitched in the fluff of his hoodie which she was using as a blanket.

It was getting really hard to reconcile this Frisk with the demon that plagued his nightmares with its cold smile and empty eyes.

"...No Sans... Not 'nother 'dog..." She slurred, making him chuckle despite himself.

Frisk squirmed again and took a long huffing breath, waking up. She cracked her regular, dark eye open and a smile touched the corners of her mouth to find him there. Sans felt a deep blue blush steal over his cheekbones despite himself.

"Mor'ning." She mumbled, now smiling fully at his bashfulness.

Sans sat up quickly, rocking the boat a little.

Luckily, the alternate River-Person took this opportunity to _finally_ reach their destination. And of course, instead of pulling up to the Waterfall dock like he'd asked, they found themselves at the base of the Hotland plateau. Still, Frisk gave the trolling River Person a grudgingly polite 'Thank you' as they disembarked.

As they ascended the stairs up to Alphys' Lab Frisk returned Sans' hoodie to him. It smelled like soap, dirt and human but he didn't mind as he pulled it on.

Suddenly, a loud -BOOM- shook the cavern, jarring Sans out of his pleasant mood.

 _fine. break time's over._

Frisk took the remaining steps three-at-a-time and Sans struggled after her, quickly out of breath. The room beyond them was covered in rubble and thick with swirling rock-dust. However, Sans thought he could make out shapes fighting in the haze.

-CLANG- -CRACK- -SWIFF-

Sans and Frisk both hit the deck as a crimson energy-spear was deflected in their direction. It crackled over them and lodged itself with a heavy -THUNK- in the cave wall behind them.

They barely had time to exchange a surprised glance as the ceiling and wall behind them gave way, blocking their retreat and sending them scrabbling forward into the war-zone.

"Stop it, Undyne! You'll hurt him!"

Frisk's eyes widened in confusion as she heard her own voice call out in alarm. Her fingers brushed her lips, as if to check if it _had_ been her after all.

No. As the particles in the air settled an alternate version of Frisk came into view. She was younger and obviously terrified. There was also something wound around her shoulders that-

Sans knew that if he'd had blood it'd be boiling right now as he laid eyes on _Flowey_ of all monsters coiled around the alternate Frisk protectively. He had no time to process this, however, as a line of thick bones burst from the dry ground and arced in all directions. Alternate Frisk dodged clumsily to one side but not quickly enough. She cried out as one of the magically charged bones clipped her ankle.

The younger Frisk struggled to stand on her damaged ankle, the dimming soul over her chest throbbing with fear. Without giving her time to react, a new phalanx of bones carved through the dirt towards her. She was finished.

The girl screamed, not even trying to evade when suddenly Undyne appeared in the path of the bones and countered them with a few vicious, well-placed stabs of her spears. Splinters of bone clattered harmlessly off her black armor with its red heart emblazoned across the chest.

"You alright, punk?" The alternate Undyne hissed, her pose protective as she stood between the human and... _Papyrus_?

Sans could feel his mind stall as it ran into a wall of pain at seeing his brother, even as an alternate self.

"I... t-think so." Alternate Frisk nodded, chugging a Sea Tea and rising to her feet again, healed.

"Thanks, Undyne!" The sickly-sweet voice of Flowey called out from over AltFrisk's shoulder.

"NYEH HEH HEH HEH!" The red-and-black clad Papyrus cackled, a cruel smile stretching his skull. Sans' soul ached at the familiar laugh. He was so busy staring he didn't even notice his Frisk start running. "YOU HAVE TRAINED ME SO WELL, UNDYNE! IT'S REALLY TOO BAD. THAT I'VE GOT TO KILL YOU NOW!"

With another grating cackle the dark Papyrus thrust both of his red-gloved hands forward. Pale bones burst from the ground on either side of his tall form, sending his blood-red cape fluttering around him. Undyne valiantly deflected the brunt of his attack but there was too much for any one monster to deal with, even her.

One sharpened femur stabbed unexpectedly out of the ground directly in front of where Undyne was standing, too far inside her spear's effective range.

"NYEHEHEH... HEH?"

Everybody took a moment to process the young woman in the striped sweater who had suddenly materialized between Undyne and the killing blow. Frisk's expression seemed impressed with herself as her fingers curled around the bone protruding through the right side of her chest and out her back. Then she crumpled to the ground as the bone disappeared.

" _ **no!**_ " Sans was at Frisk's side an instant later, taking the same shortcut she had. Memories flashed through him as he pulled her into his arms. So many memories of holding Frisk's lifeless corpse, full of sadness, vengeance or often both.

Undyne stood stock-still behind him as Sans cradled Frisk's body, confusion and terror rolling off her in palpable waves.

"B-BROTHER?" The alternate Papyrus took a step back as well.

Only the alternate version of Frisk had the courage to ACT.

"Flowey! Use your 'friendliness pellets'!" She cried in her youthful voice as she skidded to a stop on her knees beside Sans. As Flowey nodded uncertainly, Sans felt his eye flash threateningly at the manipulative plant. Flowey wilted under his gaze but summoned a number of bullets that swirled around the Alpha Timeline Frisk's white-and-red soul as un-menacingly as they could.

"It's okay. He's going to help." Alternate Frisk put her thin hand on Sans' shoulder as he jerked his Frisk away from the bullets. It was only the sincerity of the young child's gaze that made him drop his guard a little. He'd always been a sucker for that look.

The "friendliness pellets" hit Frisk's soul with little echoing blips and Sans watched in amazement as her half-and-half soul burned more and more brightly until it was at full strength. She stirred in Sans' arms, healed but still unconscious.

"uh, thanks?" Sans said to Flowey who was staring at him with a face more fearful than Sans had ever seen on the weed. It nodded meekly.

"S-SANS? WHAT ARE. YOU DOING?" The dark Papyrus stepped back a little, confusion writ plain across his empty eyesockets.

Sans shot the alternate Undyne a glance that read: ' _protect her with your life or you're gonna have a less-than-optimal-experience_ '. She nodded hastily as he handed his Frisk over to her.

Standing, Sans struggled to keep his soul from manifesting as he confronted his brother.

"i should be the one asking _you_ that, papyrus." Sans took a few steps towards the black-clad skeleton. "that human," Sans jerked a boney thumb at the LOVEless human cowering behind Undyne, "seems pretty innocent ta me. since when did you kill innocents, huh?" San's blue gaze was piercing.

"BUT YOU WERE THE ONE. WHO TOLD ME TO KILL HER. AND TAKE HER SOUL?" Papyrus seemed unsure of himself now, his fingerbones clicking nervously as he clutched his hands together.

Sans stopped his advance, remembering that this was not _his_ Papyrus. Absorbing the knowledge that his alternate self had ordered his precious brother to murder an innocent human.

" _ **did i**_." It wasn't a question. Papyrus nodded frantically nonetheless.

"I THOUGHT. YOU WOULD FINALLY BE PROUD OF ME. IF I BROUGHT YOU HER SOUL." This Papyrus looked so beaten, it hurt Sans to look. "POINTLESS, PATHETIC, POSSIBLY THE MOST USE USELESS EXCUSE FOR A MONSTER YOU'VE EVER SEEN. THAT'S PAPYRUS. THAT'S WHAT YOU SAID."

Sans couldn't bear to hear any more of this. He sidestepped through a shortcut and appeared in front of the taller skeleton, drawing him immediately into a deep hug. The taller skeleton made a little squeak of fear and seemed torn between pushing him away and trying to de-materialize like a ghost.

They stayed like that for a long time.

.

.

At Sans' urging the six of them returned to Undyne's house in Waterfall (without using "fast"travel, this time). It was uncomfortable for Sans to be in the house now considering what had happened last time he and Frisk had walked through that door, but it seemed that the normally-murderous Undyne was the only one in this universe that wasn't completely out of her goddamn mind.

Sans was absolutely not used to walking around this much and practically collapsed into a chair once they arrived. He sipped the tea Undyne had made for everyone, wishing it were ketchup as the silence stretched on. Frisk was resting peacefully on the couch as the alternate Flowey ministered to her wound.

It was the alternate Frisk, watching the unconscious, older version of herself warily that spoke first.

"You're not from this timeline, are you?" She asked, staring at Sans dead in the face with that blank expression of hers.

"something like that." Sans answered, flinching as Papyrus sprayed him with tea in surprise.

"I KNEW SOMETHING WAS WRONG WITH YOU!" Papyrus cried, his voice loud enough to shatter glass. Sans dabbed his skull off with a handkerchief that Undyne wordlessly supplied. "YOU WOULD NEVER BE SO... NICE." Papyrus' expression crinkled in fear as he realized what he'd said. His posture became hunched as if he were expecting to be hit at any moment.

The lanky skeleton visibly jumped as Sans' eyes landed on him fully.

"i'm not like the brother you know, 'pparently. you don't gotta worry about me ever hurting you, paps." Sans tried to put all the sincerity he could into his voice but it seemed this version of Papyrus had been hurt too many times to let his guard down. It made him want to get his hands on the Sans that had abused his poor brother so terribly and rip him to shreds.

"SO YOU. DON'T WANT THE HUMAN'S SOUL?" Papyrus asked quickly, perhaps thinking that Sans' angry expression was meant for him. Sans smoothed his grin out as best he could, trying to rein in his temper.

"no. i don't."

The tension in the room lessened dramatically.

"So why are you here, then?" Undyne asked, speaking up for the first time. Sans had to think carefully about how to answer her, not wanting to cause any more confusion.

"this version of the human and i... got lost." He wasn't exactly lying. "we're trying to get back to our own time 'n just happened to show up when we did. thing is, i know my human." Sans grinned a little wider. "she won't want to leave again until we've helped you guys. never could stay out of a fight, y'know?"

The other monsters and human didn't seem to totally understand but at least they weren't completely terrified of him anymore. That was a start.

"so tell me. why's everyone so afraid of me here?" Sans asked, knowing he'd probably regret the question. Undyne and Papyrus shot each other a look that spoke volumes, each trying to get the other to talk. Papyrus broke first, bless his soul.

"WELL. YOU'RE SORT OF. KING OF THE UNDERGROUND."

Sans couldn't help a little quirk of amusement at hearing that, but his look bid Papyrus to continue.

"YOU KILLED ASGORE."

San's amusement snuffed out immediately.

"AT FIRST. EVERYONE WAS UPSET. THEY REBELLED. IT DIDN'T LAST LONG." Papyrus looked extremely uncomfortable to be telling him this and Sans had to resist the urge to hug him again. This Papyrus didn't like hugs very much. He'd fix that if he could.

"That was when I quit the Royal Guard." Undyne said, playing with her hair nervously. "I didn't want any part of your - er, _his_ tyranny. I trained Papyrus in secret, hoping that he could assassinate our Sans when he was strong enough. However..." She trailed off, giving Papyrus a nasty glare.

"SORRY." Papyrus seemed crestfallen.

The younger Frisk walked up to Papurys and sat between his femurs on Undyne's chair. She rubbed his patellas lovingly which seemed to calm him down a little.

"SOMETHING HAPPENED. WE'RE STILL NOT SURE WHY, BUT THE HUMAN SOULS... SUDDENLY DISAPPEARED." Papyrus was looking into his tea as if for answers. "MY SANS... TOLD ME IT WAS THIS HUMAN. ORDERED ME TO KILL HER FOR IT."

Sans' breath caught in his ribs as he puzzled out exactly _who_ had stolen them. It would seem that since Gaster existed outside causality, the human souls had been simultaneously removed from every possible universe. The remembered pain of struggling against the flames of Gaster's god-like power made the lights in his eyes burn brighter.

"We'll... help you get them back." Frisk, _his Frisk_ slurred from the couch as she struggled to prop herself up on her elbows. Flowey tried to get her to lay back down but she was too determined.

"R-REALLY?" The dark version of Papyrus asked, hope peeking into his nasally voice.

"and _i'm_ going to teach your sans how to treat his brother properly." Sans stated, feeling his magic leap at the prospect of Judgement.

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.

Papyrus paced around the bottom floor of Alphys' surface lab for what felt like the thousandth time, his orange cape trailing behind him. Toriel's worried gaze followed him restlessly from where she sat at Alphys' cluttered desk.

"HOW LONG CAN SOMEONE SPEND IN THE BATHROOM?!" He cried, waving his hands in the air. The shoulders of Sans' hoodie were wider than his but even if they made his erratic gesturing feel awkward he refused to remove it. He'd return the hoodie to Sans when they got him back.

He knew it was irrational, but he just couldn't bring himself to believe his brother was gone.

"Patience, Papyrus Sweetie." Mettaton had unfolded Alphys' bed from its easy-to-draw cube and brought it downstairs so he could lounge seductively on it. He certainly had nice legs, Papyrus thought, distracted momentarily from his impatience. "Come, sit with me."

Mettaton patted a place beside him on the comfortable mattress and rolled over into a languid position with his legs in full splits. Papyrus grumbled and sat down beside the robot. He felt Mettaton's extendable arms wrap around him possessively.

"Alphys is very smart. She built _me_ after all." Mettaton winked. "If she says she'll do whatever she can then that's what she'll do."

Papyrus blushed nervously as Mettaton planted a quick kiss on his skull behind where his ear would have been.

The door to Alphys' bathroom swiffed open before things could progress any further (regrettably).

Papyrus was up and looming over her in an excited instant. "DID YOU FIND ANYTHING?"

She gave him an uncertain look that made his smile deflate.

"W-well... I l-looked into some old... f-files. R-really old. I f-found something." The diminutive dinosaur-monster pulled out a strange device that looked like a cross between a TV remote and a taser.

Papyrus took it from her claws to examine it more closely, despite her squeak of alarm. "WHAT DOES IT DO?" He asked, turning it this way and that. Alphys fidgeted nervously, worried he'd start pushing buttons.

"N-n-n-not sure. I-it's v-v-v-very d-dangerous, P-Papyrus!" She sputtered, too short to grab it back. "T-the notes said. I-it c-could ch-change timelines l-like ch-ch-channels on T-TV. Um. H-hold still one s-second."

Papyrus watched as she clipped a thick, metal bracelet around his ankle. He tested it with his fingers and found it to be very sturdy. He'd probably have to remove his foot to take it off.

"T-that is a t-tracker. S-so I can monitor you f-from here." Alphys pressed a button on the keyboard of her big-screened computer after scooting Toriel aside. An icon of a grinning Papyrus hovering over a dot appeared on the monitor. His icon was very small, however, among the countless other dots that dappled the screen, interconnected by confusing lines that seemed to shift as he watched. Sciency stuff was really more of his brother's thing.

Next, Alphys attached a smaller version of Papyrus' tracker to the vial containing Sans and the human's soul shards. Papyrus snatched that up to look at it more closely as well. Another dot appeared on the map of timelines. A little heart: half white, half red. Papyrus felt his soul clench in anticipation. The heart was on the other side of the map, but it was there.

"W-we'll have t-to be v-very c-careful about- _Papyrus N-!_ " Alphys shouted as Papyrus pressed the big, heart-shaped button in the middle of the device.

.

Papyrus dropped the timeline remote as it suddenly started burning his fingers, hot enough to actually damage him.

"UH OH." He said, kneeling down to examine the little device where it started to spark and smoke. That couldn't be a good sign. "SORRY ALPHYS, I-" Papyrus stopped as he realized his surroundings had changed. He wasn't in the lab anymore. With a sinking feeling he realized he might have made a mistake.

Like the time he'd tried putting limes in his eyesockets as a spa treatment.

Well, nothing for it but more limes.

Now that the device had stopped smoking, Papyrus carefully picked the charred thing up off the ground and tucked it into his Battle Body armor beside his trusty Sharpie and the vial containing Sans and the human's soul shards. Taking a closer look around, he was surprised to find himself in Asgore's Throne Room, which he had seen only once before as a little babybones. His and Sans' dad had been there talking to the King about something important. However, all he remembered from the experience was the beautiful garden of flowers that carpeted the room, lush and fragrant under the genuine sunlight that filtered in through the crystals in the ceiling. He'd never seen sunlight before since he'd been born right after the monsters migrated Underground into what was now The Ruins.

At least, that's what he thought? For some reason his memories felt fuzzy. Probably because he'd been so young.

Either way, this throne room was nothing like the one he remembered. Sunlight still filtered onto the ground, but no flowers grew here. The ground seemed churned up as if by violence and the area around the throne itself was singed black. The top half of the throne was also missing, as if blown away by some incredible destructive force. There was also a neat pile of mustard bottles lined up behind the throne.

Very strange. He'd never have imagined Asgore would secretly drink monster alcohol. He was famous in the Underground for his love of tea.

"H-Hello?" A timid voice called out from the entrance of the room, distracting Papyrus from his thoughts. It was a young child, so thin and pale they were practically a skeleton themselves. Papyrus decided that it was not a good look for a human, no matter how cool skeletons were.

"HELLO! I AM THE GREAT PAPYRUS! WHO ARE YOU?" Papyrus initiated the introductions.

The human flinched at his voice (probably because it was so awesome) and seemed to draw into the green-and-yellow-striped sweated they were wearing, a pained look flashing across their red eyes.

"I'm not important." They whispered so softly Papyrus had to strain to hear.

"PLEASED TO MEET YOU, 'NOT IMPORTANT!" Papyrus chattered, oblivious to the joke he'd just made.

The human actually smiled at his repetition of their name, seeming to draw strength from his endless well of greatness.

"I'M A LITTLE LOST. WOULD YOU MIND TELLING ME. WHERE I AM?" Papyrus continued, walking up to the youth who was still cowering in the doorway. "I'M LOOKING FOR MY BROTHER. LITTLE SKELETON. CHUBBY. SMILES LIKE 'THIS'!" He hooked his forefingers into his jawbones and tugged his face into a passable impression of San's lazy grin. At least, that's what Undyne had said when he'd showed her. Between fits of giggles as she rolled around on the floor.

The child seemed to close off a bit, as if in fear. They turned aside contemplatively.

"I've been here for... so, so long. But soon he'll have the last soul and I'll be free..." The child mused. They wearing some sort of collar around their neck, the underside of which looked pink and irritated. "If I tell you when to find Sans... will you help me get out of here when the time comes?"

"WELL I DON'T SEE WHY N- OH. UM HUMANITHINKTHEREMIGHTBEAKNIFEINYOURBACK." Papyrus rambled through the sentence, quickly grabbing the human by their frail shoulders and turning them around. They tried to struggle, but were too weak. Yes. there was definitely a knife sticking out of their back. Humans were so strange, he decided.

"No! Don't touch that!" The child cried, making Papyrus let go in surprise. The human turned back to facing them, seeming exhausted by even the small effort of struggling. "If you take it out I'll... I'll..." The human stopped suddenly, all remaining color draining from their face as she stared at something over Papyrus' shoulder.

" ** _you're back soon, bro._** "

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* * *

 ***Dramatic Organ Music*  
**

 **Also, some mention of Papyrus and Sans' dad! Oh, who _ever_ could _that_ possibly be? _ **

**.**

 **Next chapter in two days! (Wednesday) Thanks everyone for all the support! You guys are awesome!**


	8. Chapter 8- UNDERFELL PT3

**Ahahahaha! I promised that I'd get the next part out on Wednesday and here we are at 11:45PM!**

 **I was torn forever on whether or not to make UF!Sans a total jerk/badass. However, it wouldn't be Undertale if the character you originally thought was the most terrifying turned out to be completely misunderstood...**

 **Then again, Sans always was an exception to the rules.**

 **Also, current list of AU options: UnderSwap, Fusion, HumanTale, Bromalgamate, Outertale, GasterBlaster, HaremTale  
**

CHAPTER 8- UNDERFELL PT.3

" _ **you're back soon, bro.**_ "

Papyrus knew right away that the Sans who now confronted him was definitely _not_ his brother. He wasn't nearly as dense as people thought he was, after all, and for all his moods, laziness and awful puns Papyrus' Sans was ultimately a good person.

This Sans was definitely not.

" _ **where's the human soul?**_ "

This Sans was leaning on the burnt throne, smirking arrogantly at him in a way that made his golden fang flash in the dim sunlight. He took one clawed hand from the pocket of his black hoodie and used it to straighten out the little golden crown that was sitting on his sweaty skull. Asgore's crown. Red magic smoldered in Dark Sans' left eye, giving off a scent like burnt sins.

Beside Papyrus, the frail-looking human seemed to go very still.

"YOU'RE NOT MY BROTHER!" Papyrus snapped, taking a few brave steps forward and feeling his soul appear on his chest in anticipation of a fight. He stepped in front of the human and hoped it wasn't too obvious that he was shaking.

Dark Sans' brow crinkled for a moment as he took in the sight of Papyrus gathering his magic. Then his cruel eyes went wide in shock.

"you... you're not..." The impostor Sans actually staggered back a few paces which made Papyrus feel like maybe they weren't such a villain after all. Maybe he was just scared?

Papyrus let his defenses drop slightly and started taking measured steps towards the strange Sans, arms out at his sides so he wouldn't spook him. Papyrus knew that when his brother was scared he started making puns. This must be avoided at all costs.

"I THINK I MIGHT. BE LOST?" Papyrus said(shouted) which only made the chubby skeleton who was now practically hiding behind the throne shrink further. Papyrus motioned for the little human to come with him. He'd show them there was nothing to fear. "SORRY FOR SCARING YOU."

"scared? _**me?**_ " The other Sans stepped out from his cover with an obvious effort and glared up at Papyrus as he approached. Papyrus gave him his best smile.

"I DO TEND TO STARTLE MONSTERS. WITH MY GREATNESS." Papyrus struck a pose.

Alternate Sans and Chara exchanged an incredibly vocal glance. Chara shrugged.

"no. you're definitely not _my_ papyrus." The dark Sans' red-pupiled eyes flared with a sudden intensity that caught Papyrus' attention. He wondered if it hurt to keep his magic concentrated like that.

Despite the obvious differences from his own brother, Papyrus couldn't help but empathize a little with this version of Sans. He knew his brother used to struggle with keeping his magic under control and remembered some of the really bad nights where he had to hold his brother to relax him enough that he could fall asleep. He wondered why the Papyrus in this timeline hadn't done the same.

"where you from, then?" The strange Sans asked suddenly. His tone was perfectly neutral but the expression he made was like someone was tickling the inside of his ribs. His skull was so drenched in sweat that his crown was starting to slide off.

Unperturbed, Papyrus told him. Withholding some of the key details (Like the fact that his version of Sans had _died_ ), he told these two strangers that he was looking for his version of Sans and had reason to believe they were somewhere in... wherever he was now. Papyrus really didn't understand much of it.

This version of Sans seemed to bleach about three shades lighter.

"You're from a different timeline?" The human child seemed fascinated, getting over her earlier fear of him and the fake Sans finally. "And you're not alone?"

"SOMETHING LIKE THAT? AND I'M NOT... TOO SURE. WE GOT. SEPARATED?" Papyrus lied, rubbing the back of his skull.

"It's finally happening, Sans!" The humans' face was lit up with joy now but for some reason it didn't strike Papyrus as 'happiness'. Their eyes were too wide. "That prophesy old Gerson used to blab about before you- uh." The kid's eyes flickered to Papyrus' face. "The one about the Underground going empty!"

" _ **not if i can stop it**_." This Sans practically snarled and it was Papyrus' turn to take an involuntary step back. He didn't understand why he was suddenly so angry. What was going on? " ** _an' i thought i told_ you _to stop sneaking around, chara. why the hell did ol' king gore keep you around anyways?_**

Papyrus really needed his brother to deal with these sorts of things.

"Same reason you do." The human child whimpered, drawing behind Papyrus' cape. "I know a lot about humans. More than anyone else down here. I'll be useful when we get to the surface."

" ** _heh. as a_ pet _, maybe._** " Sans hooked his red magic into Chara's collar and dragged her out from behind Papyrus before he could react. " ** _and i've got some bad news for you, kid. we're not_ going _to the surface. ever._** " He held the girl off the ground by her throat, slowly rotating in his field of magic as she kicked and struggled.

"P-PUT HER DOWN! RIGHT NOW!" Papyrus shouted, stepping forward to help.

There was a sudden pulse of magic and then something hit the back of his skull. Hard.

.

.

Papyrus woke on an uncomfortable surface to the quiet noise of claws tapping on a keyboard. He opened an eyesocket and was surprised to discover he was in a cage. They'd tricked him! He'd trusted that impostor Sans and that human child to help him and they'd knocked him out!

This really wasn't turning out to be a very good day.

Suddenly, The memory of that grey Sans staring up at him with those empty eyes reared its ugly head. He remembered the feeling of his brother's dust drifting through his fingerbones. He didn't see how things could get any worse as he curled into a ball and stifled a sob.

His brother _wasn't_ dead _,_ though. He'd find him.

"Y-you're alive!"

Papyrus uncurled so fast in surprise he banged his head on bars of the small cage, adding to the pounding headache that was already there courtesy of a certain mean, fake skele-jerk.

Papyrus tried to find the source of the voice in the dark room and was glad to recognize the familiar head-crest of Dr. Alphys silhouetted against a large computer screen. Oh, thank goodness! He was worried that everyone had suddenly gone-

Oh no.

The Dr. Alphys that scurried up to him now was another impostor. She seemed a little taller than the Alphys he was used to but was hunched over so far that she ended up being the same height. Her expression looked like she really had to go to the bathroom and her glasses were so foggy he didn't think she could even see through them.

"Who knew that the alternate universes were s-so _weak_? I thought you would f-fall for sure after just o-one little bone attack. I-I mean. This is good. Now we can do the experiments." She continued, approaching the bars of his cage with a curious expression.

Papyrus realized the bars of this cage were way too close together for him to slip between them. Now that just wasn't nice. Wait. Did she say experiments?

"EXPERIMENTS?" Papyrus asked aloud, feeling his earlier fear returning in force. He pulled his legs back towards himself as this Alphys tried to grab the tracker band on his ankle. "HEY. I NEED THAT! SO THAT... ALPHYS CAN TRACK ME?"

The dinosaur monster looked amused at that. Her thin lips curled into an imitation of a smile.

"So it _is_ t-true. You're from another timeline? Or m-maybe another universe entirely..." She mused, letting a forked tongue slip between her lips briefly. "Ehuhuhu, so that's why King Sans was so n-nervous around you. He's r-really p-paranoid about space-time travel."

She clutched the bars so hard Papyrus could hear the metal squeak. He really didn't like this Alphys.

"Which he should be, ehuhuhuhu," she laughed mirthlessly, "because it's all going to end soon."

"WHAT. DO YOU MEAN 'END'? WHAT'S GOING TO END?" Papyrus shouted in a shaky voice as Alphys hunched back to her computer, still laughing. She ignored him however and then seemed to become agitated by something she saw on the monitor.

"S-stupid malfunctioning robot! You're supposed to _kill_ the humans, n-not _entertain_ them!"

.

.

Frisk and Sans exchanged a confused glance as this universe's strange parody of Mettaton blocked their way into Asgore's castle. This robot had four arms and two visible eyes but the way he moved was devoid of their Mettaton's sultry charm and grace. This one just seemed desperate.

"Are you not amused?" This Mettaton asked, spinning plates with all four of his hands.

"LET US IN, STUPID ROBOT." Alternate Papyrus screeched, clearly having been subjected to these antics before and Alternate Undyne also seemed like she was revving for a fight. The little version of Frisk and her pet demon-flower merely watched timidly from behind the armored fish-monster.

"hey, don't be that way, bro," Sans chastised. Even though he knew this Papyrus wasn't _his_ brother, it still bothered him deeply to see any Papyrus so angry. Alternate Papyrus shot him an aggravated glance but acquiesced.

Mettaton dropped his plates, suddenly staring at Sans in alarm. Sans sighed. He was getting real tired of this.

"Master! I... I didn't recognize you! Please, please don't deactivate me!" Mettaton was suddenly grovelling at Sans' feet, making him extremely uncomfortable. His relationship with the overly-affectionate robot had been stretched even in his own universe. This was just weird.

"yeah, yeah, i get it." Sans awkwardly helped the terrified robot stand back up. This Mettaton seemed very confused at the situation which Sans figured was about par for today's course.

"We need to get to the throne room." Frisk (the _real_ Frisk) stated, taking charge as usual. "The elevators are all down."

"Oh." Mettaton said, starting to juggle nervously. Sans figured he'd be a good juggler too with four arms. "That would probably be Dr. Alphys. She's under orders not to let anyone see... er... you." Mettaton was staring at Sans more intently now as if trying to process what was going on. His juggling had gotten blindingly fast. "I'm not supposed to let... anyone in?"

"so. if i'm here. then you won't let me see myself?" Sans' grin quirked as he watched Mettaton practically blow a circuit as his logic processors overloaded.

"Well... Yes. I mean _no_! I mean..." Mettaton looked frantic.

Sans gave the impression he'd be raising his eyebrows if he'd had any.

The room smelled like hot robot.

"Follow me, Master." Mettaton seemed to have regressed back to basic command protocols. Frisk shot Sans a look that seemed to ask if tormenting the poor robot was really necessary but he just gave a short chuckle in response. The rocks that the alternate Mettaton had been juggling clattered to the floor (some of them complained at the rude treatment) as he turned to lead them into the castle proper.

The alternate Papyrus and Undyne were chattering about battle strategies for when they confronted "King" Sans as the party meandered through Asgore's old house and on through the empty streets of New Home. Alternate Frisk seemed nervous and withdrawn, but her older self from the Alpha timeline was holding her small hand and offering reassurance. Sans let himself drift as he listened to the noise of his Frisk's calming voice.

It was so strange, that after all the terrible crap this human had put him through that he should now feel so protective over them. He remembered reading in a washed-up human medical textbook about something called Stockholm Syndrome, wherein someone who has been held in isolation for long enough eventually starts to love their captor.

He tried to remember Frisk as she'd been the first time he'd seen her: Wide-eyed and so very young. And covered up to her elbows in Toriel's dust. He shuddered at the memory, feeling the familiar rage warm him up inside.

There was a strange ripple in the air then that brought Sans out of his brooding. His eyes flickered over the young girl who had suddenly gone quiet, a determined look on her face. Must've just saved.

Alpha Frisk seemed to have noticed as well considering the unsettled glance she sent him. Her left eye glowed slightly with his borrowed power and it made him uneasy. Even after all they'd been through recently, Sans didn't want to allow himself to trust her fully.

Mettaton stopped suddenly in front of a huge set of double doors.

 _He_ was on the other side, Sans could feel it. The air in the corridor was thick with the stink of magic left burning too long, and of mustard.

Alternate Flowey coiled tightly around Alternate Frisk as the doors began to grind inwards, bathing them in the red, refracted glow of sunset from the Surface. Papyrus and Undyne had gone deathly still and San's Frisk wound her fingers between his skeletal ones. He could feel the echo of their shared soul linking them.

Not wanting to face this demon alone, Sans held Frisk's hand tighter.

As the doors opened, they were greeted by a human child in a green-and-yellow sweater. She seemed surprised to see them, but the expression on her rosy-cheeked face was oddly blank. Her eyes seemed to be staring right through them.

"You... tricked us?" She asked quietly. At first Sans thought she was talking to him...

...Then she slumped face-first into the dirt, dead.

There was no sound of a soul breaking. Feeling a pang of recognition at the fallen child, Sans realized they'd probably lost their soul long ago. At least that explained why Gaster hadn't taken this child's soul instead. Why he still needed the younger Frisk's red heart.

Alternate Sans was standing behind her, holding the knife.

Time seemed to slow to a crawl as everyone tried to understand what they'd just witnessed. Sans figured he deserved a moment to process, considering he'd just watched himself commit murder. He wondered disjointedly if he should feel guilty. The version of himself that was currently brandishing the blade and grinning at them like a cat in a larder certainly wouldn't.

The alternate Frisk dove forward before anyone could react.

"Chara!" She cried, hugging the other child's slim frame to their chest and getting crimson blood all down the front of their sweater. Tears were streaming from the girl's frantic face. "Big Sis!"

 _oh._ Sans grasped the next piece of the puzzle but couldn't find where it fit.

But it looked like they had bigger problems.

"C-calm down Frisk!" Flowey cried, snapping Sans back to the present. The weed was coiled around Frisk's arm, trying to restrain them as the girl pointed at a blank space in the air. Like magic, words appeared:

SAVE, LOAD, RESET.

 _oh no. nonononono._

Sans tried to move, but he was stuck. Everyone was frozen. Paused. In the corner of his field of vision Sans could make out his Frisk's terrified expression. He'd have been glad at her finally getting her just-desserts at being forced into a RESET if it hadn't meant they were all about to die. If that meant he'd never get to see his brother again and tell him everything would be okay.

The little finger hovered over SAVE for a moment that stretched forever.

But then the little girl's face darkened as she realized that she'd _just_ saved in the hallway. They wouldn't be able to go back far enough to stop this. Alternate Sans was grinning like he'd orchestrated this. But _why?_

Her palm came down on the RESET button with the force of a guillotine.

Time hiccuped.

And the little girl disappeared.

* * *

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 **Get ready for the angst train again, people! choo choo!**

 **I just gotta say I love writing Papyrus as a really naive, trusting guy. He's not completely oblivious and his first impression of someone is almost always right... he just tries so hard to believe there's good in everyone. ;_;**


	9. Chapter 9- UNDERFELL PT4

**Okay so here's the final chapter of the Underfell Arc! Man was this arc as a whole fun to write, and I especially enjoyed trying to adapt the original AU designs and mentalities into a cohesive headcannon that I was really happy with. More notes on this at the end of the chapter!**

 **In the mean time, I'd like to thank everyone for all the support and loving reviews/PMs everyone has sent. You have no idea how much it means to me and how much even the smallest comments inspire me to keep writing. (This angst train needs fuel, babeh!)**

 **So, in the spirit of audience participation, it's finally POLL TIME! I've got a bridge chapter planned (it's one I've wanted to write almost from the start of this fic and I think you'll really like it). But while that's happening I'd like to get everyone's votes on which AU Sans and Frisk should visit next.**

[POLL FINISHED]

 **.**

 **.**

 **For recommended music Youtube:** _ **Undertale Megalovania Dual Mix**_

* * *

WHATEVER CAN HAPPEN WILL

CHAPTER 9- UNDERFELL PT.4, SANS VS. SANS

.

Time started again but still nobody could bring themselves to move. Even Alternate Papyrus and Undyne who had no idea what was going on had been able to infer from the other's reactions that something really, _really_ bad had just happened. Mettaton simply had a melt-down and powered off. Flowey let out a choking sob, then disappeared into the ground.

Frisk let go of Sans' hand and dropped to her knees, seemingly in prayer.

"we're... still here." Dark Sans stated, looking at the knife he was holding like it'd betrayed him.

"BROTHER! WHAT IS HAPPENING? WHERE DID THE HUMAN GO?" Alternate Papyrus asked, moving towards his brother. Sans wanted to reach out and stop him from getting too close to the skeleton with the knife but stopped when he realized that there was nothing he could do for this Papyrus now. He and Frisk had to escape quickly, if they still could. "AND WHY DID YOU KILL CHARA?"

" _ **shut up, papyrus.**_ " Alternate Sans commanded, silencing his taller brother with a red-tinted glare. But there was fear in those eyes now, too. Something hadn't gone according to plan.

"I THOUGHT YOU WANTED. TO GET THE SEVEN HUMAN SOULS. AND GIVE THEM TO FATHER?"

" _ **i said**_ **shut up!** _ **if you'd forced the human to reset earlier like i ordered you to, these time-hoppin' goody-two-shoes wouldn' have ever been a problem!**_ _"_

 _father?_ Of everything he'd just heard for some reason that cut through the confusion in Sans' mind.

Sans stepped forward, leaving the still-kneeling Frisk in Undyne's protection for the moment. Other Sans seemed equally curious and cautious of his doppelganger and held his ground as Sans approached, though his skeletal hand visibly tightened on the hilt of Chara's knife.

"care to explain, buddy?' Sans asked with barely veiled menace. He knew he was more prone to making mistakes when he was emotional, and if it came to a fight Sans wanted his opponent to be worked-up and stupid. "why'd you force the kid to reset like that? and who's your father in this timeline?" He let his blue magic burn in his eyesocket for added effect.

He hadn't expected his counterpart to start laughing hysterically. Even Alternate Papyrus was looking at him with a tinge of amusement now. Sans kept his grin perfectly neutral despite feeling like he was missing out on an inside joke.

" _ **aheheheheheh! what kind of backwards timeline d'you morons keep comin' from?**_ " Dark Sans had to hold his crown in place as he bent double in laughter. Sans desperately hoped that someone would explain the joke to him but the manic laughter just stretched on and on, echoing in the barren throne room.

 _wait. did he just say '_ keep' _comin' from?_

Sans asked what Alternate Sans meant by that but his only response was a cruel smile.

Sans was starting to lose his cool.

"i asked you a question." Sans reiterated, taking another few steps towards the black-clad brothers. He only stopped when he was nose-to-nose with his dark mirror-image, though he was hyper-aware of the knife his double still wielded. He'd felt that knife's edge before and had no intention of _ever_ feeling it again.

Dark Sans sobered up quickly, rubbing a lingering tear of laughter from his cheekbone with the sleeve of his hoodie.

" _ **i had everything under control, y'know? until you, the girl an' that other noisy walkin' bag 'o bones came bargin' in on my timeline.**_ " The grin on the other Sans' face turned hostile in an instant. " _ **but i dealt with the other skeleton easy 'nuf. and now you're ne-**_ "

Sans was on him in an instant. He grabbed this PoS excuse for a Sans by the scruff of his hoodie with one hand and clocked him solidly in the face with his other fist. The impostor went flying from the magically-augmented attack and rolled a few times before coming to a stop on the ground near the windows on the far side of the room. Sans had never actually _punched_ someone before and he even thought he might have broken one of his knuckles. But _damn_ if the other Sans hadn't had it coming.

Alternate Papyrus was looking at him like he'd been betrayed as Sans strode past him towards where Dark Sans was struggling to get back up.

 _sorry evil-paps, you never deserved any of this_. He apologized to the dumb-struck Papyrus internally.

The golden crown the alternate Sans had stolen had gone flying from the force of the hit and Sans picked it up on his way over to where his double was shakily getting to his feet.

" _ **you sayin' another papyrus came through here**_?" Sans couldn't keep the magical echo from his voice. The idea that his brother had somehow been dragged into this hellish timeline with him was too much to bear. Especially considering that this universe had just been rigged to reset with them inside it.

The alternate Sans now had an ugly crack above his right eyesocket. In growing horror and rage, he traced the contour of the break with fingers sharpened into claws. His red eyes pulsed dangerously as they took in Sans standing there with his crown.

It occurred to Sans that he'd hit his doppelganger much harder than he'd intended. He'd have to learn to control his new strength.

It also occurred to him that his doppelganger was made of tougher stuff than he was, since that hit would've blown his 1HP to kingdom come.

" _ **an' why should i tell**_ **you** _ **anything?**_ " Dark Sans spit out a fang that had come lose and Sans felt the Red Magic closing in around him.

They both stood in silence. Sans twirled the crown around his fingerbone, trying to agitate his enemy into making the first move. Near the entrance, Frisk still seemed to be concentrating very hard on something, judging by the way her face was all scrunched up. She seemed to be actually sweating from exertion.

 _is she holding the timeline open?_

They didn't have much time, Sans realized and felt his soul manifest over his sternum. Dark Sans' eyes widened greedily as he took in the half-human soul and then a predatory smile stretched his gold-toothed mouth.

" _ **because we're all gonna die soon unless you talk. Frisk and I can jump ship before the reset with as many of you as we can carry. even you. jus' tell my where my little brother is.**_ " Sans felt his magic building to a critical mass. There was so much _more_ of it now, he was starting to worry about whether he'd be able to control it properly.

" _ **you think i**_ **want** _ **to survive this? this is just me giving dear ol' dad the middle finger! he can't order me around anymore. i'm the**_ **_king now!_** " The alternate Sans shouted and lunged forward with the knife. It slashed through empty air.

Sans re-appeared behind his doppelganger and struck with a few well-aimed shards of bone. He didn't want to kill him. Just incapacitate him to the point where he could get the information about where Papyrus was. He'd tear his other self apart bone by bone if he had to.

.

.

Papyrus watched his brother fight the impostor Sans from his prison with wide eyes. Alphys was alternately cheering and booing at the computer screen like she would during an especially exciting fight in one of her animes.

But this was real.

His brother was _alive_.

Papyrus held his gloved over his mouth to smother a sob of relief.

It was difficult to keep track of the two monsters as they blipped around the screen, dodging each other's attacks by simply _not_ being there when they landed. Bones appeared and disappeared without warning, carving through the room and often barely missing the other monsters trapped in there with the dueling skeletons. Every once in a while the Evil Sans would strike out with a knife, but soon realized his magic had much better reach. Papyrus' eyes were wide as oblong saucers as his big brother dodged at the very last second when a flurry of bones appeared at point blank range, aimed for his eyes.

"GO SANS!" He cheered, making Evil Alphys give him an annoyed glare.

Now that he looked, Papyrus could see his human girlfriend was alive as well, though she seemed to be hurt, or at least focusing very hard on something. Undyne was there too and... Papyrus' jaw practically fell to the floor when he noticed a black-armored version of himself on the screen. He looked... _so cool!_

Suddenly Alphys cried out in anger and pounded her fists on her work-desk at something that had happened during the fight, sending some sort of device clattering to the floor. Papyrus' eyesockets widened into oblong dinner-plates when he realized that the object was a carbon-copy of the timeline-switcher the original Alphys had given him.

.

.

Dark Sans' eyesockets went wide in rage as he opened his mouth to shout only to find it already full of his crown which Sans had teleported between his fangs. San's grin morphed into the shit-eating variety as his counterpart realized what he'd done.

"chew on that." Sans winked.

" _ **raaaaaagh!**_ " The alternate Sans bit clean through the metal and redoubled his attack, making up for the humiliation.

Sans dodged and dodged and dodged as the ex-king-of-monsters activated his Gasterblasters and sent line after sizzling line of white energy in his direction. The last and most powerful of which actually singed the fuzz on one of his slippers!

He was getting desperate.

Each skeleton tried his best to wrap the other in an incapacitating field of magic to try and control the other's movements but neither could find any purchase. Their magic was just too similar and kept slipping off.

Sans charged up his own blasters, feeding them with the raw emotion and hate that gave them their power when suddenly a startled gasp came from the entrance of the room.

 _frisk!_

Sans' worst fears were confirmed as he turned to find the alternate Papyrus had put her in a headlock that had her squirming helplessly a meter off the ground. The castle itself rocked as Frisk's concentration shattered. They were out of time.

"Traitor!" Undyne lunged towards Papyrus but pulled up short as the tall skeleton held a sharpened bone dagger to Frisk's neck. The alternate Papyrus looked about as frantic as Sans felt, and he seemed to be looking to his brother for guidance.

" _ **kill her!**_ " Dark Sans cried, releasing a volley of bones at Sans to keep him pinned in his corner of the room.

"You'd betray us all?! You'd betray me?!" Undyne shouted, her red energy spears crackling in her gauntleted hands. "This isn't who you are, Papyrus. Don't let your brother turn you into this!"

Papyrus looked torn as his gaze flicked back between his brother and his mentor. It hurt Sans' soul to see him like this, even if it wasn't _his_ Papyrus. He dodged another vicious slash of bones and sent his own wave out, missing his target by a wide margin in his distraction.

Frisk was trying to say something but Papyrus' grip on her neck was too tight and her face was turning red.

" _ **i protected you, you useless bonehead!**_ " Dark Sans roared, now letting off his attack momentarily as well. The room seemed to twist sideways as the RESET closed in. The Castle itself was collapsing. " _ **whenever father got angry at you, who was there to take the beating?! i shoulda' never done that for you! i made you**_ **weak!** "

 _so that's why this sans is so tough._

The gloved hand gripping the dagger tightened.

"Please Papyrus. You're not a murderer." Undyne pleaded.

"I. BROTHER, I..." Papyrus was shaking now.

"don't do it paps." Sans said, trying to pretend like he was talking to his own little brother. Trying to push his fury away. The alternate Papyrus looked up with orange-tinted tears in his eyes. "a real brother would love you no matter what."

There was a long, stretched silence that was filled with a weird white noise.

The dagger clattered to the ground as Papyrus collapsed to his knees, releasing Frisk.

" _ **no!"**_ Dark Sans cried like a wounded animal. He summoned the biggest GasterBlaster Sans had ever seen and aimed it at the other monsters and Frisk.

.

.

Outside the castle, the horizons of the Underground were getting blurry. Even the distant roof of the massive cavern that held the bastion of New Home had lost its glimmering gems that shone like stars over the capital. The only light now came from the city itself which had begun to glow as the CORE beneath it overloaded. One of the castle's red-tiled towers collapsed as the bedrock beneath it ceased to exist.

In a massive explosion, one side of the castle's uppermost tower erupted outwards, sending stones the size of houses crashing to the streets below. A small figure was ejected from the tower a moment later so quickly that they left a trail of smokey debris in their wake, like the Underground's first and last shooting star.

Dark Sans collided with another tower so hard he left a crater in the red tiles that had barely cushioned his landing. Chara's knife went flying from his hand and flipped end-over-end into open space. He exhaled in a ragged gasp as he felt his ribs break.

" _ **still not as bad as dad was.**_ " Dark Sans hacked, his fanged mouth curving upwards painfully.

" _ **what kind of sick parent could've turned me into you?"**_ Sans had appeared behind his counterpart just in time to hear his admission. A Gasterblaster was poised over each of his shoulders, trained on the alternate Sans' dimming soul. Sans had both of his hands shoved into his pockets casually but the sweat dripping down his forehead and into his eyesockets revealed just how exhausted he was.

The cruel-looking skeleton laughed at that, stopping only to cough up a bit of some yellow fluid. Sans actually had to resist the urge to help him up. He knew exactly how the other Sans was feeling and the fact that he knew Frisk and the alternate Undyne and Papyrus were surely watching them only made him feel more guilty.

He'd come too close to losing control with that last attack. The magic had flared up so suddenly in him when Frisk had been immediately threatened that he hadn't been able to stop himself from firing with everything he had at his doppelganger. And even then it had been a near thing. He'd taken out Dark Sans' blasters only a split-second before they'd fired.

Sans raised a hand to wipe off his skull and paused in surprise. The contours of the bone seemed different. Distorted almost. He really hoped he hadn't done any lasting damage to himself.

" _ **you really -**_ cough- _**have**_ no idea _ **?**_ " The red magic seemed to have finally drained from the alternate Sans' eyesockets and had been replaced by two pinpricks of light. The area under his eyes looked dark with pain and exhaustion, even through his fanged grin had returned.

Sans saw that grin for the mask it was.

" _ **no. i don't.**_ " Sans said in response, needing to learn how his alternate self could have a father while he and his Papyrus had not. The light from the CORE below was becoming blindingly bright, overwhelming even the bright blue fire that streamed from his left eye. " _ **and where is my papyrus?**_ "

The alternate Sans let out a tired chuckle, his eyes seeming to linger on Sans' face a little too long, as if tracing the contours.

" he's prob'ly already dead. 'e was in that tower over there in alphys' lab." Dark Sans gestured to the collapsed tower that was now nothing more than a heap of rubble. Papyrus was tough, but nobody could survive that.

Sans felt his bones go liquid at the news. He fell to his knees without even noticing, the blasters over his shoulders winking out as his magic fled him.

"no." Sans whispered, feeling like he was being crushed by a giant fist. "no. not again. please god no."

The alternate Sans chuckled painfully again. He tried to raise his cracked head and failed. Another line now split the other Sans' left cheekbone from the eyesocket to the corner of his mouth.

"gaster. my father was gaster." Dark Sans admitted, the edges of his body seeming to waver and flake off, becoming dust. "he died a long time ago when i pushed 'im in the -cough- core. but he came back. took the souls and tol' me to take that human's as well. with seven souls he... well. y'know how it is. -cough cough- i wanted to make the -cough- human reset so gaster couldn't... i won't be the sans to give 'im what he wants. i'll burn in hell first."

Sans' eyesockets went wide at the revelation. Gaster had failed to get Frisk's soul in the Alpha timeline due to his intervention so he was going to go through every conceivable universe in order to get what he wanted. And when he did... they'd all learn the real meaning of a _bad time_. Sans felt a kaleidoscope of memories unravel in his mind as all of this sunk in. He remembered Gaster not just as his boss or as the royal scientist... The man had been his father, too. And Papyrus'.

 _papyrus..._

Right now they had to leave. He placed his palm on the other Sans' forehead and teleported them both back to the throne room, or what was left of it.

Dark Papyrus rushed over to his prone brother and gathered him into his arms, weeping.

"I'M SO SORRY, SANS. I... I COULDN'T KILL THE HUMAN." He cried, running his fingertips along the cracks in his brother's face. His breath hitched as the alternate Sans raised his own hand to cup alternate Papyrus' cheek.

"no paps. i'm sorry. this is -cough- all my fault." This voice seemed wavery, like it was turning to dust as well.

"NO NO NO!" This Papyrus cried, holding his shorter brother against his breastplate. His orange tears were already falling into the pile of dust that covered the ground beneath them. Undyne stood at attention, though her gaze was averted. She was crying too.

"We can take you with us, if you want." Frisk offered. She took a step towards the alternate Papyrus but paused when she saw the orange hatred burning in his eyesockets.

"KEEP YOUR PITY, HUMAN. LEAVE US. NOW." Dark Papyrus pulled himself together just enough to tell her off. He wouldn't even look at the original Sans, who had backed away from the emotional scene.

Frisk looked to Undyne, but she just shook her head. This was the end for her, too.

Sans held his hand out for Frisk to take. They were done here. They'd failed. After all this effort, he only had more questions than he'd started with. At least... now that Papyrus was dead, they didn't have to hurry anymore.

Delicately, Frisk reached out and wiped away the tears Sans hadn't even noticed he'd shed. She didn't know yet about Papyrus. She didn't know that he was crying for his own selfish reasons, despite the heartbreak and death that surrounded them. Sans felt like a sham.

"We need to go." She said quietly, taking his hand.

Not trusting himself to speak, Sans nodded and stepped to the side holding Frisk tight against him. There was a slight squeeze as they passed between the folds of time, a moment of weightlessness, then-

.

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* * *

 **I did warn you there would be feels! not quite as bad as Chapter 5 was, but still not the best day for everyone involved. Also I really hope Papyrus found a way to grab that remote O_O**

 **And, because I'm sure that people will get confused I'm just gonna explain exactly what the nature of Gaster's plan was (it felt weird making UF!Sans do exposition and I'm worried I made him a tad too cryptic O_O) So basically, Gaster is back to playing an active role in the timelines after taking a long hiatus from, well, existing. This influence manifests a little differently in every timeline. However, his goal is always the same: acquire Frisk's soul. Having failed to do so in the original timeline (he can't use the Frisk\Sans souls because they're not full-human anymore. Also he learned his lesson last time he tried) he'll just keep trying his luck in every timeline until it works.**

 **Gaster had an abusive relationship with UF!Sans and UF!Papyrus, so when Gaster approached UF!Sans after he killed UF!Asgore about getting the seven human souls, breaking the barrier and then presumably reigning as a god over the whole of causality... UF!Sans was less than enthused. However, because you can't just say no to an extra-dimensional God, he decided to play along. Internally, he planned to force the UF!Frisk to RESET even if it meant bringing their timeline to an end. It was better than giving Gaster what he wanted.**

 **In this universe, Chara exists as Frisk's older sister, who has been kept as a sort of slave first by Asgore and then by Sans. Over time, she's become accustomed to her captors and views murder in a highly pragmatic, if regrettable way. Therefore, she'd been excited for when Frisk's soul would be taken and everyone released to the surface, including her. When UF!Sans kills her, it's because that's the last way he can think of to make UF!Frisk RESET. And he would have gotten away with it too, if it hadn't been for that meddling skeleton! (and human)**

 **.  
**

 **Whew. Sorry about all that. I'm pretty sure it's lazy writing if you have to explain everything again afterwards but meh. There it is ;P**

 **Instead of being miffed at me please go check out this fabulous fic by** starlight1395 **which is based on my version of Underfell. It's called 'Purify The Timelines'**


	10. Chapter 10- MEMORIES

**This chapter is a bit of a stand-alone and will cover the memories that Sans gained access to at the end of Chapter 9. I swore I'd never stoop to bone puns but they're just so perfectly cheesy ;P**

 **Thade Dreemur belongs to: Roskiiuniverse. You can find them and their beautifully menacing version of Asgore's dad on tumblr. :)**

.

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* * *

WHATEVER CAN HAPPEN WILL

CHAPTER 10- MEMORIES

Sans' first memory was of running through the dark. In a funny way he'd come to spend his entire life doing just that, he realized distantly.

{{{{{The angry humans were gaining on him as he stumbled and crashed through the forest underbrush down the side of the mountain. Their torches sent lancing rays of light through the dark, foggy air that served to light his way, if only barely. The barking of hounds cut the early-morning silence.

Sans yelped as he tripped over a protruding root and ended up tumbling. He lost all track of where he was as his world closed to a distant ache and a strange, watery feeling in his bones. The only thing he knew for certain was that something was seriously wrong with his right shoulder since he could only feel it as a bright splash of pain.

The sounds of his pursuers seemed muffled, and it wasn't until Sans opened his eyes that he realized why: He was underwater.

The four-year-old skeleton-monster stayed perfectly still under the surface of the shallow stream he'd fallen into and wished the muddy stream-bed would just swallow him entirely. Better than being caught by humans. He'd heard so many _horrible_ things about them. Like how they fed babybones to their dogs.

A little cry of fear escaped him as heavy boots splashed through the water around him, followed by the braying of those scary hounds. The humans seemed confused.

From the bottom of the stream, Sans looked up and watched what looked to be the leader of the human mob draw an arcane sigil in the air meant to hone in on his magical signature.

Sans waited for the moment when the spell triggered and he was revealed.

...

...

Nothing?

Suddenly there was a great burst of violet light from further down the mountain that made the human mage look up in alarm. An instant later a bone the width of a small tree impaled him clean through the chest and carried him off his feet with its momentum.

"Sans!" A familiar voice called, though it was distorted by the water. Feeling hope flood his rib cage, Sans sat up and felt the sounds of battle become immediate. However, he felt unbalanced and was surprised to find his right arm lying dislocated in the stream beside him. He grabbed it and ran towards the purple light.

His dad was surrounded by humans and was looking between them frantically, the white dots that were his eyes scanning everything for some hint of his son. Despite his obvious fear the tall, regal-looking skeleton was holding his ground against the human mob. The sheer power of his magic made his white cloak billow around him in a way that made the humans not want to get any closer, especially after seeing what had happened to their mage. Violet fire streamed from both of Sans' dad's eyesockets and his long-boned hands clicked between magical symbols faster than Sans' eye could follow.

"Dad!" Sans cried, bursting through the line of humans before they could notice him.

His father's gasp of relief at seeing him (even if he was holding one of his arms in the opposite hand) made Sans' heart leap with joy. He was safe now. He'd never go exploring alone again, he promised.

The humans noticed the tall skeleton's break in concentration as he scooped his babybones son up into his arms and charged in as a unit.

But by the time they struck, both skeletons were gone.}}}}}

.

{{{{{Sans looked over his shoulder at the horde of monsters that trudged raggedly into the gaping cave-entrance in the side of the mountain. They'd lost the war. King Thade Dreemur was standing before the mage-king of the humans at the tail of the procession. The once-proud king with his thick mane of dark hair and wicked-sharp horns was being made to kneel in surrender as his son, Prince Asgore watched.

Barely four-and-a-half now, Sans held tightly to both his parent's hands and followed them into the waiting darkness. His mom looked down at him with worry in her eyesockets, but her ever-present smile made him feel more at ease. Sans thought she looked pretty in the orange head-shawl she was wearing, an heirloom from her own mother. Everything they'd wanted to keep they'd had to carry on their backs.

As the humans sealed the cave behind them, rock by rock, Sans felt the growing distress of the monsters around him. His mother was crying a little now and his dad was trying to comfort her by rubbing her between the shoulder blades as they hugged. He was careful not to knock her pregnant tummy.

It was getting darker now, as the last bits of open sky were blocked off from them. Sans watched until the very last bit of twilight-blue disappeared to the blackness. Everyone was perfectly quiet then, feeling the stifling atmosphere under the mountain closing in, threatening to break them.

San's mom knelt carefully to be at eye-level with Sans. "Hey, cheer up." She hooked one of her long, delicate fingers into the hole between his shin-bones. " _Tibia_ honest, I'm scared too." Her hand drifted up to his knee-cap, "and _patella_ the truth things will be different from now on. But that doesn't mean they can't be..."

"mom noooooo..." Sans whined as she wiggled him by his humerus bone. She was smiling bravely, though there were tears on her cheekbones. She seemed so strong as she summoned gentle blue magical fire that curled from her eyesockets and pushed back against the darkness.

Sans' dad gave his wife, Romana, an indulgent smile. He loved her jokes no matter how groan-worthy they got. Sometimes he'd even try to match her wits in pun-offs. It was one of his worst pel _vices_.

Helping his wife back to standing, W. D. Gaster smiled, drawing on her well of strength. He was glowing with magic now, too, rebelling against the black.

Around them, like a slow, luminescent wave, all the monsters that could activated their magic. A rainbow of sparkles, ribbons, flames and even spears lit the cavern, thrumming like a single heartbeat. They may have been beaten, but they would _not_ be broken.}}}}}

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{{{{{It wasn't all bad in the Underground, Sans decided. The purple-stoned towers and catacombs of Home (So dubbed by King Thade) were warm and dry, and there were no humans to chase him or hounds to try and eat him here. Best of all, Sans had a baby brother now: Papyrus. His parents had argued over the name for a long time, but eventually Sans' dad caved and let his mom call the baby what she wanted. She was still sick from having the baby, after all.

Sans sat his bones down on a high ledge overlooking the main square of Home and watched the monsters down below bustle in the dim light. This particular cavern was the most popular location in the Underground, since there was a hole way, way up in the cave ceiling that let in a spot of actual sunlight. Monsters came from all over to visit the spot where flowers grew naturally and gave the air a nice fragrance. Even if the rest of the market square smelled like sweaty fur.

 _why do fleshy monsters have to have so many... fluids_.

Sans crinkled the bridge of his nasal bone in distaste. Skeletons were so much cooler. Also, it helped that without any organs to nourish skeletons didn't have to worry as much about stuff like eating. At least not in the way that squishy monsters did. They definitely enjoyed food and needed it to grow, but ultimately their energy needs were much lower. Any excess just went into the magic that held them together to be used later.

Which was good, because the Underground was running out of food.

Sans' family was very lucky since his dad was the Royal Scientist for the Underground. His work in developing a source of power to help grow food was crucial to the survival of all monsterkind, which was why Sans' family lived in relative luxury compared to most others. His mom always reminded him to be grateful for what he had and Sans tried his best. It was just that he could only stomach so many water-sausage casseroles before he lost his mind.

"Now Sans, we're lucky that we have anything to eat tonight at all." His dad chastised him as he stared sullenly at his plate. He was the one who cooked dinner now that his mom was having trouble walking around. She'd given too much of her soul to the baby, the physician had said.

Sans huffed, wanting something more flavorful. Then, he spotted an open bottle of some red sauce on the counter. It smelled really good and Sans knew it was probably a luxury item in the scarcity of the Underground.

He reached out with his hand towards the bottle, concentrating on it like his cousin Calibri had told him to when they'd practiced magic together. Or rather, when Calibri had practiced his Blue Magic and Sans had done exactly nothing. As always. Felling a little frustrated, Sans edged over to the counter while everyone was distracted and reached for the bottle.

However, Baby Papyrus picked that moment to blow his cover by squealing with joy and pointing directly at him.

"Woah there, sweetie!" Sans' mom called out, using her magic to lift the bottle out of his grasp. Sans' dad also turned around in his chair.

"That stuff's not for baby bo-"

The bottle crashed to the ground, splattering the floor and Sans' feet with the red sauce.

"Romana!" Sans' dad cried as his wife collapsed suddenly, falling out of her chair.

Papyrus squalled in fear, this time.

.

That night Sans had stayed with Papyrus in the Royal family's quaint little home. The young prince had tried to cheer him up by making him tea and showing him all of his favorite flowers but Sans had been too worried to smile even for the Prince's sake. He stayed awake the whole night, holding Papyrus tightly to his chest as he tried not to cry.

This was his fault. If- if he hadn't tried to get that sauce then his mom wouldn't have used her magic. If she hadn't used her magic, she wouldn't have fallen down like that.

Baby Papyrus sniffled a little in his arms, picking up on his agitation.

"hey l-little bro. don't worry, okay? everything's gonna be f-fine." Sans whispered, but the baby wasn't buying it and burst into tears. Sans couldn't stop himself from doing the same.}}}}}

.

{{{{{San's dad had started acting different after his mom fell. The funeral had been a large affair, with monsters arriving from across the kingdom to bid the beautiful, sociable wife of the Royal Scientist farewell. The urn had read T. N. Romana in sensible looking, straightforward letters.

Afterwards, Gaster had started working late every night and even when he was home he seemed distracted. The adult monsters noticed this and considered putting Sans and the now walking-and-talking Papyrus in the care of another family, but Sans' dad had fought for them vehemently.

Sans remembered the crash from downstairs and the flash of violet light that lit up the second-floor landing of their house as his dad scared the well-meaning monsters away.

"They're all I have left!" He'd heard his dad shout, "you'll never take them from me!" Followed by the angry slamming of the front door.

Afterwards, Gaster had come upstairs to sit with Sans on his bed and hold sleeping Papyrus in his long arms. The way his clothes hung on his skeletal frame told Sans that his dad hadn't been eating properly.

"are they gonna take me 'n paps away?" Sans asked, sniffling a little.

"No. I'll never leave you boys. Not ever." Gaster kissed Sans on the top of his skull, a little spark of magic making the spot tingle warmly. "I know I've been busy, and I hope one day you'll forgive me. But monsters are beginning to starve. There just aren't enough resources in Home for everyone."

"then couldn't we just go? aren't there other caverns down here?" Sans asked. He'd seen the huge stone doors that led deeper into the mysterious depths of the mountain.

Gaster became thoughtful.

"The rest of the caverns were sealed for a reason, Sans. There's uncontrolled magic down there."

"but if people are dying..." Sans played with the joints of his dad's fingerbones which were wrapped around his shoulder comfortingly.

"You know. That's actually not a bad idea." Gaster mused, and Sans was glad to have helped.

"DADA!" Papyrus cried, now waking up a little. He was growing fast and was already up to Sans' pelvis.

"I'll make sure you two are safe no matter what. But you'll need to be brave. How are your magic classes going, Sans?"

Sans shrunk into himself then, ashamed. He hadn't been able to access any magic at all. He was a _freak_. He shook his head.

"It's alright son. I know you're destined for big things. It's only a matter of time."

Sans wasn't so sure.}}}}}

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{{{{{The trek out of Home was the biggest challenge monsterkind had faced so far, mainly because of how weak and desperate they'd become. At first it was only the poorest monsters who left to brave the cold of the Snowdin Mountains in hope of finding greener pastures on the other side. Then, once word got back about Waterfall and Hotland, the mass exodus really began.

Sans sat around one of the group campfires and tried to be grateful for the measly scrap of water-sausage he was picking at. His mom would've wanted him to be. At least he didn't have to worry about being cold, like the shivering, reptilian monsters were.

Papyrus was scampering around with a group of children, joyful as always. The sight of it made Sans grin, though the expression felt unnatural on his face. He figured that his mom would want him to smile, to keep up the morale of the others if nothing else.

"NYEHEH HEH! YOU'LL NEVER CATCH ME! OOF!" Papyrus had been in the middle of preparing a snowball when one of the slightly older kids, a fish-monster named Undyne dumped a snow poff the size of a small boulder on his head.

"Take that, Nerd!" She shouted, dancing around the pile of snow with Papyrus' squirming legs sticking out of it.

"MMMMMMMMF!" Came Papyrus' muffled shriek. About time for Sans to intervene, then.

"c'mon undyne. stop pickin' on my bro." Sans said as he put some backbone into pulling his brother out of the 'poff. It didn't make it any easier that his bro was turning out to be a lanky bag of bones like their dad. Undyne just laughed at the two of them, striking a pose with her head back and hands on her hips. It didn't help Sans' morale that once he dragged Papyrus out of the snow he started looking at her in hero-worship.

"I will, when he learns to defend himself!" She laughed, then stopped abruptly when Sans shoved a handful of snow (which he'd been hiding tucked into his rib cage for just such an occasion) down the front of her coat.

"heh. chill out, undyne." Sans grinned and it felt more natural this time. Papyrus clapped his hands in glee before grabbing up another pile of snow and dumping it on Sans' head.

"GOT YOU!" Papyrus chirped, seeming on the verge of another 'NYEH HEH HEH'.

"so it's war, then?" Sans winked out the lights in his eyes and gave his little brother the scariest face he could manage. Papyrus' eyes went wide with fear, but it wasn't directed at Sans. It was directed at Undyne behind him.

"You're DEAD, punks!" Undyne, despite being as old as Sans was, seemed to tower over them with a murderous look in her eyes.

"ruuuun!" Sans shouted and the two skeletons scattered.

The snowball war that ensued ended up drafting the majority of the monster kids in Snowdin and even some of the adults. The adolescent Prince Asgore (who's family were finally making the trek further into the underground) was recruited on the side of the Skelebros Corps. and was used effectively as a meat-shield by Sans as he orchestrated guerrilla-style runs on the enemy Fish Faction.

Both brothers were howling with laughter and sopping wet as they returned to their family's private tent that evening. It didn't matter that they only had nice creams for dinner because their bellies were full of laughter.

Even Gaster, who'd been working himself to the bone on his plans for sustainable energy sources laughed as Papyrus regaled him with hugely exaggerated stories of their battle.

Sans found the courage to say something he'd been meaning to for a long while:

"dad. i want to be a scientist like you some day."

Gaster's smile shrunk a little, but there was a sudden look of pride in his eyes.

"R-really?" Gaster asked, motioning for his boys to climb into his lap on the floor of their tent. They'd always sit like this before bed so he could tell them stories. This time though, Sans' dad had a more serious look in his eyesockets. "Being a scientist is a lot of hard work, and it's not very satisfying most of the time. You're definitely smart enough for it Sans, but you're so young to make such a big decision."

Sans blushed blue at the praise. He'd thought this over a lot, actually, and had even been eavesdropping on the Prince's mathematics and science lessons.

"i... this is gonna sound pretty dumb, but i wanna help monsters be free again. you're working so hard to help us live down here which is awesome... but i want paps to see the sky someday."

Gaster's expression seemed to cloud over a bit, though the warmth in his eyesockets didn't dwindle one bit.

"WHO NEEDS THE SKY?" Papyrus chattered(his voice probably audible five tents down the row), crossing his arms. "I'M HAPPY RIGHT HERE!"

Gaster rubbed Papyrus' skull lovingly, smiling at his enthusiasm.

"i know, paps." Sans said, working up to the next part of his admission. "but also... for a kid like me, with only 1HP and no magic, i'm not really good for much else."

"Don't you talk like that, Sans." Gaster gently took Sans' chin between his fingers and turned him to look up at his face, illuminated only buy the warm light of candles. "You can do anything you put your mind to. It might be harder for you, but with enough determination anything is possible."

Sans didn't fully believe him, but grinned anyways.}}}}}

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{{{{{Gaster's face was beaming with pride as King Asgore handed Sans his diploma. The blonde-haired goat-monster was still wearing his mourning clothes after his father's falling but he smiled warmly when he and Sans shook hands. Ten years had passed since Sans had decided to become a scientist, and after a decade of grueling studying, memorizing and pulling all-nighters... he was ready for the hard part.

Papyrus' cheers drowned out literally everyone else in the small auditorium situated on the fringes of Hotland. Sans blushed furiously blue as people stared at him and tried his best not to trip over his own feet as he walked off-stage to join the other graduates. They had all studied in drastically different topics, but given that only a handful of the already tiny proportion of monsters ever bothered with higher education they were all going to celebrate graduating together.

"T-this is so embarrassing." Alphys, one of Sans' closest friends in the science department muttered to him. "C-can't they just m-mail us our diplomas or something?"

"c'mon al, you don't gotta go _postal_ about it." Sans whispered.

She stifled a little snort.

"what, you don't gotta _stamp_ down on my jokes so hard. or is it just the _delivery?_ " Sans continued, his grin slowly consuming the lower half of his face.

That combo-attack earned him a full giggle which Alphys quickly covered up with her claws. Sans liked it when he could make people laugh. It made people like him, he'd found. And as much as he'd tried to convince himself during his adolescence that he didn't care what people thought of him, he did.

He'd rather be the comedian over a nerd or weakling any day.

Right then, however, as Sans gave a little wave at his Dad and Brother in the audience, he genuinely felt good about the skeleton he'd become.}}}}}

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{{{{{Work in the Royal Laboratories between Hotland and the growing capital of New Home wasn't exactly like Sans had imagined it. It was a lot duller, actually. Nobody would ever run through the halls shouting 'Eureka!' on the heels of some great scientific discovery. Nobody would so much as chuckle at his jokes before being dosed with enough caffiene to kill a greater dog. Nobody really took much interest in him at all, really.

Preliminary work on the CORE was going well, and Sans was playing a peripheral role in it, but sometimes he longed to be right in the center of the action. He wanted to participate in his dad's work with determination and harnessing the magical power that flowed from the heart of the Earth.

Sans sighed and rubbed the bridge of his nose between his fingers. The mathematical formulae he'd been constructing had begun to dance in his vision.

"stay still, stupid numbers." He muttered to himself and pulled a mug of coffee towards his mouth but realized it'd gone cold. He set it back down. How long had he been working for? When had he last eaten? Sans didn't know.

He looked up suddenly at a commotion in the corridor. A monster had just run past at break-neck speed, lab-coat flapping dramatically and everything.

 _finally, some excitement!_

"what's the hub-bub?" Sans asked as he trotted into the lab common room, out of breath from running. Everyone in the facility was present, looking serious and worried, including W. D. Gaster.

"D-Dr. Gaster's gonna tell us. I-I think." Alphys whispered to him. She looked sweatier than usual.

"Calm down! Everyone, please calm down." Sans' dad was using his height to his advantage as he shouted over everyone's head. He looked uncomfortable in the spotlight when everyone turned to look at him but he adjusted the lapels of his lab-coat and powered through. "I know a lot of you have probably heard the rumors by now, and they're true. At least, most of them. Probably. "

Gaster lost control of the room as a storm of excited shouting swept through. He just waved his hands frantically, unsure of how to regain their attention.

"what rumors? dad, what's happened?" Sans had finally forced his way through the throng to where his dad was standing. Sans might not have been as tall as his dad or brother, but at about the height of an average human male he was still head-and-shoulders above many of the other scientists.

"Sans! I've been looking for you everywhere!" Gaster exclaimed, gesturing with his hands like he did when he got excited. "A human fell into the Underground."

Sans felt the lights in his eyes grow distant as he absorbed the news. This would change _everything_.}}}}}

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 **Hope you guys enjoyed this! I always wanted to explore the time-frame right at the end of the Monster-Human War and this seemed like the perfect time to throw this in. This won't be the last 'Memories' chapter, though. Maybe I'll do one between each major story arc? :)**

 **Also, can I get a Drum-roll for the winning AU which will be featured next?**

 **DRRRRRRRRRRRRRRRRRRRRRRRRRRRRR**

 **UnderSwap!**

 **This next week I'll be working up in Northern Canada so I'm not sure how much time I'll be able to allocate to writing or what the internet connectivity will be like. I'll try my best to get the next chapter out by Wednesday at the latest, though. (And I've got a nice, 7-hour drive to think of some fun scenarios and swap-themed puns. ooohhh yessssss)**

 **Update from up North: Internet is definitely a 'go' up here. Expect the next chapter Monday or Tuesday!**


	11. Chapter 11- UNDERSWAP PT1

**I'd like to mention that the original title of this chapter was something else but I felt that it gave away too much so I changed it. ;D The new title does still fit this pretty well I think. heheh. heh. O_O Don't blame me for this I wasn't the one who asked for UnderSwap!  
**

 **And speaking of UnderSwap, I got a review last night that asked me to include a summary of what AUs I'm including for those who aren't "in the loop". Details of this AU can be found on Tumblr on the 'underswap AU' blog: underswapped . tumblr . c om Essentially, it's an AU where all the character's personalities are flipped. i don't want to talk much about it here because it would reveal some junk that goes on later in this chapter. ;P  
**

 **This takes place instantly after Chapter 9 by the way, which is why it starts so abruptly.**

 **So without further ado, here's a bit of Sans/Frisk bonding and a skele- _ton_ of fluff.**

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WHATEVER CAN HAPPEN WILL

CHAPTER 11- UNDERSWAP PT.1 - TRASH

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-fell straight into waist-high water.

"agh!" Sans sputtered as the sudden current pulled Frisk off her feet into him. The memories which had consumed him during their transit between universes faded into the backdrop as both of them toppled into the turgid water.

"Over -pft- there!" Frisk breached first and dragged Sans by his arm over to a nearby island made exclusively of golden flowers. He considered being less of a dead-weight for a moment but was too exhausted both emotionally and physically to move at all.

He'd failed. Papyrus was dead. They hadn't saved _anyone_ for all their efforts in that past universe and oh. Right. _Papyrus was dead_. His incredible brother had transgressed the laws of space-time to rescue him and Sans hadn't even been able to meet him half way.

Sans couldn't bring himself to make even the minimal effort to climb onto the island and relied on Frisk to pull him ashore, and it was only because he was incapable of drowning that he'd let her pull him from the water at all. Frisk was breathing heavily from the exertion as she laid down in the soft flowers parallel to him.

"I think we're in the Garbage Dump?" Frisk said to the cavern ceiling, clumsily pushing her sopping wet hair out of her eyes. When Sans turned his head to look at her, her left eye was a spot of stark blue among the yellow blooms. "What universe do you think we're in now?"

Sans grunted non-commitally at her questions, putting all his effort into _not feeling_. It was eerie how easy it was if only he let the lethargy take him. He was so tired...

Frisk said something to him that he didn't hear.

He could still see the alternate Sans' sadistic grin as he'd told him that he was too late to save his brother. That Sans had thoroughly enjoyed causing him pain. However, the worst part about the whole nightmarish situation was how Sans knew despite everything that that Sans was still _him_. The circumstances of their lives had been very different, but at the core of things they were both the same monster.

When Sans had fought Frisk in the Judgement Hall what felt like a hundred lifetimes ago he'd enjoyed the feeling of smashing her into the walls and pillars. He'd reveled in his own power as he skewered her, blasted her, dunked her and watched the slowly building frustration on her normally smirking face.

Gaster had been a good father in his timeline and it seemed that having such a supportive upbringing had been his one and only tether to morality, considering how far he'd fallen to his sadistic urges even in a relatively peaceful universe.

"Sans!" Frisk broke into his thoughts by shouting at him. His eyesockets felt so dry. "Sans, I said 'it's not your fault.' Okay? You did the best you could. They couldn't have been saved." Frisk continued, wiping a few tears from her cheeks.

"it _is_ my fault. that sans was _me_ , frisk. the worst part of me... but still me." The heavy-set skeleton spoke slowly, trying his best to keep his emotions from his voice. Internally he decided not to tell Frisk that Papyrus was dead. She had enough to deal with already.

She frowned, rolling over to rest on her elbow and look down at him. her dark hair was like a veil over her regular eye, leaving only the magical one exposed. Sans felt naked under its gaze but hid the truth nonetheless.

"You can't hold yourself accountable for _everything_." She said softly, that blue eye tightening in sadness. "But I can. If anyone's responsible for all this it's me. You don't deserve anything that I've done to you. After everyone I've killed."

Frisk seemed to retreat into herself then, her childish expression of hurt incongruous with her teenaged features.

"that was chara, not you." He refuted, raising himself to his elbow as well without even realizing it.

She shook her head in a way that made her eye twinkle like a dying ember. "Eventually, sure. By the time I fought you, I was trapped in my own mind by her... it was terrifying..." Frisk shivered. "But not at first. I'd played the same series of events out over and over again. I'd gotten curious, like Flowey had. The choice to kill was _mine_."

Sans didn't know how to deal with what he was hearing and decided he didn't want to hear any more of it. Not now, at least.

"you're not the same as that _weed_." Sans spat, reaching out to hold Frisk's forearm firmly but compassionately.

"No. I'm _worse_ than he was." Frisk was practically sobbing now and Sans felt an overpowering urge to comfort her, despite his own near-unbearable pain.

"listen to me frisk. that's. _not. true_. time travel does crazy things to a person. look at gaster, he used to be an incredible dad but now he's an abomination. and that's without having a psychotic parasite living in his head." Sans realized too late that he'd just compared her to the power-crazed-creature-from-the-void that had made their lives a living hell and made them watch as their friends realized they were dead.

At least he was able to hold her as Frisk broke down in his arms.

"hey. hey. i didn't mean it like that." He sighed, as she pressed her face into the nape of his neck. She was so soft. Sans couldn't bring himself to say that she really _wasn't_ anything like his dad, because in a lot of ways their journeys into madness and/or murder had been very similar. Like he'd said: Time travel does crazy things to a person. He would probably be Exhibit C in that particular case.

"frisk, for _crying_ out loud, won'tcha _tear_ me out?" Sans chose the tried-and-true method and to his relief she seemed to calm down a little at his awful puns. "everybody makes mistakes, but you learned from yours. gaster didn't."

"Was he really -sniffle- your dad?" Frisk asked blearily, her voice still muffled by the wet fluff of Sans' hood.

Sans nodded, feeling an old grief stirring in his chest. He'd had a long time to process what had happened to his dad, even if he couldn't consciously remember it.

"I'm sorry that all this happened. I'm sorry you had to get caught up in it, too." Frisk pulled away from him just enough to look up into his eyes with her mismatched ones. Sans had to agree with her there and just rubbed her back as they both kneeled embracing each other on the little island of golden flowers.

"This reminds me of my favorite timeline. Us, together like this." Frisk said quietly and looked away, suddenly blushing.

Sans lifted one of his boney brows. Though the two of them were nearly the same height, Sans was by far the broader of the two and his arms seemed to completely encompass her small frame. If he wanted to, he could activate his magic and end her life in an instant.

For the first time, the thought of killing _Frisk_ disgusted him.

"tell me about that timeline." He rumbled, pulling her closer toward him. He desperately needed a distraction from his overactive mind.

Frisk tilted her head up slightly under Sans' chin and he felt her arms find their way between the inside of his unzipped hoodie and the T-shirt underneath. Light fingers traced the bottom edge of his lowest rib through the fabric and the soft layer of jelly-like magic. The sensation was almost ticklish, but in a pleasant sort of way.

"We made it to the surface," she whispered, "and everyone was so happy. The humans didn't like us at first, but we convinced them that monsters weren't a threat. God, it must've been at least a decade we spent up there." Frisk's voice had taken on a faraway quality and the lazy circles of her fingers on his ribs slowed. "I lived with Toriel but would visit you and Papyrus every day. Or Alphys and Undyne, and sometimes even Asgore or Mettaton."

Sans stiffened at the mention of his brother but tried to keep his breathing even.

"I enjoyed my life with everyone, but there were always the nightmares. Except they weren't nightmares..." Frisk's fingers grasped at Sans' rib, dragging him out of his depression and rooting him in the moment. "I had... have... so much guilt. And only one person who could possibly understand."

She looked up to meet his eyes again with an expression so earnest and heartbroken that Sans felt his grin falter.

"You were my best friend, Sans." Frisk smiled at the memory, her face becoming truly beautiful in that moment between remembered joy and despair. "And as I got older..."

Sans was suddenly very aware of Frisk's hands against his back as her fingertips brushed against his vertebrae. Lightly, maybe even teasingly? It sent a shiver up his back that felt way too good for comfort.

"stop that." Sans ordered, his voice completely flat as he grabbed Frisk's elbows and pulled her to arm's length. His neutral grin was back and his eyes were half-lidded in deadly seriousness. "whatever sans that was, i'm not him. you've hurt my friends and family too many times for there to be _anything_ between us. _**ever.**_ "

Frisk tugged away from his grip, but he wouldn't let her go.

"we're going to find gaster, get the souls back and break the barrier in our own universe. that's all, capiche?" His eyes had dwindled into the barest glimmers of light, like the distant ends of tunnels. Still, he couldn't help but remember the feeling of her fingers on his spine.

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The silence between them was heavy as they slogged through the waters of the Garbage Dump. Sans was still dangerously low on magic and resented every mundane step he took against the deceptively powerful current. Sweat beaded on his skull at the unaccustomed exercise but Frisk seemed to be having no trouble at all.

 _how they hell did she do this as a little kid?_ He thought, feeling a bit of begrudging respect for the determined human.

He gave the horn of a trashed bicycle a sad little honk as they passed it and briefly considered joking about Frisk acting _horny_ earlier... but decided that it would be in awful taste. (even worse than his usual taste in jokes)

Eventually, as the cavern widened out the echoes of voices sounded from up ahead and made them pause in alarm. Sans realized they still had no idea what sort of universe they were in. For all they knew, the monsters here could be even more vicious than the last bunch! Sans and Frisk quickly hid behind a pile of human trash and watched intently as two monsters entered via the room's Northern tunnel.

"NGAAAAH! Undyne! Y-you sure look cute today!" The louder voice shouted nervously. The strange thing was that that voice _definitely_ belonged to Undyne. Frisk's anxious gulp did not escape Sans' notice.

"Yo... your one hot hotbaby." The second voice bleated in what Sans imagined was supposed to be an alluring tone. Frisk turned an interesting shade of red which confirmed his earlier suspicions that she definitely knew what was going on here.

"What? U-Undyne! W-what's gotten into you?" Undyne sounded aghast but amused.

Sans decided he'd had enough of being held in suspense and risked a peek at the two monsters which had stopped in the middle of the cavern.

He nearly had to fish his jaw out of the now knee-high water as he saw the chubbier-than-usual Undyne wearing a knee-length polkadotted dress of all things... standing with a young Prince Asriel.

"H-hotbaby? How dare you call me that?!" Undyne had raised a hand to cover her mouth as if she were offended yet Sans could clearly see that she was smiling underneath it.

 _welp, it's settled then. this universe is going to be a nightmare._ Sans thought to himself as this strangely reserved version of Undyne rambled on about 'Baby Knights' and suplexing boulders.

"Alphys gives u a kiss!" Asriel narrated and Frisk turned a shade of red Sans didn't even think was possible for a human. His earlier frustration with her was giving way to amusement despite his better judgement.

It was only when Undyne started swooning and explaining how Alphys would at first resist their kiss but then be unable to deny Undyne's well-practiced fish-lips that Sans recalled a memory from shortly before his life had gone to hell: Papyrus had roped him into joining a role-playing game with Aplhys and Undyne and it had descended into madness similar to what he was now witnessing.

"WHAT DID YOU SAY?" Came a new, much stronger voice. Sans felt his temples ache as he saw Alphys appear in the cavern entrance in a swanky leather jacket and jeans that accented her muscular legs. She had her hips cocked to one side as she confronted Undyne and the Prince.

Sans decided he'd deal with the fact that Asriel _fucking_ Dreemur was roleplaying with chubby Undyne later.

Alphys sauntered up to the other two and asked what they were doing. Alphys tried explaining but kept stumbling over her words in a completely un-Undyne way until she was practically screeching.

"I mean, uh, Alphys... I'VE BEEN LYING TO YOU!" Undyne blurted out and then covered her mouth in shock. Sans couldn't help but be amused at the outrageous turn of events as Undyne started gushing about all the times she'd been dishonest with Alphys. The whole time, Frisk was staring at the drama with an expression of rapt attention. Sans could practically hear the puzzle pieces falling into place between her ears.

"hey kid, you know what's going on here?" Sans whispered so the others wouldn't overhear but Frisk jumped at the sound of his voice nonetheless. Luckily Undyne was still shouting at the top of her lungs so nobody heard.

"Uh. Maybe?" Frisk replied in a tiny voice. Her blue eye seemed to be glowing with a frantic energy. "I've seen this before. Whenever I did everything right and didn't hurt anyone... I'd go on a date with Alphys but it would turn into her confessing her love for Undyne. This is the same, but backwards?" Frisk's eyebrows were drawn so closely together in confusion they could have held hands.

"the same, but backwards." Sans repeated, feeling the truth of it in his bones. This revelation brought no small amount of relief, knowing that in this universe the Frisk-analog (who could only be the Prince) wouldn't be in the middle of a murder-rampage. Hopefully.

Sans and Frisk both jumped in surprise as Alphys dunked Undyne into a trashcan.

"You're PASSIONATE! You're ANALYTICAL! It doesn't matter what it is! YOU CARE ABOUT IT! 100 PERCENT! AT MAXIMUM POWER!" Alphys had a crazed expression on her face that didn't suit her at all in Sans' opinion.

"Undyne... I want to help you become happy with who you are! And I know just the training you need to do that!"

"Alphys... you... You're gonna train me?" Undyne swooned in her trashcan.

"Oh no." Frisk hissed, covering her mouth with both hands.

 _oh?_

"PFFT. What? Me?" Alphys scoffed.

 _oh no._

Sans watched in dumbfounded horror as an alternate version of himself emerged from a pile of trash like a slow-motion Jack-in-the-box.

"get those bones shakin'!" The alternate Sans shouted at the top of his lungs, wearing a too-tight tank top that read 'JOG BOY'.

 _oh no no no nononononono._

 _._

 _._

 _ **Let the fluff begin!**_

 _ **And thanks again everyone who voted in the poll! I'm sorry if your favourite wasn't chosen but rest assured I'll make my way through them eventually. It was also mentioned to me that the GasterBlaster!AU was not included in the poll. Well, let's just say there's a reason for that...**_ **;D**


	12. Chapter 12- UNDERSWAP PT2

**UPDATE: ADDED A BIG SECTION TO THE END OF THE CHAPTER BECAUSE IT FELT LIKE IT WOULD MAKE MORE SENSE THERE INSTEAD OF IN THE NEXT CHAPTER! I'VE BEEN WANTING TO ADD A SCENE LIKE THIS ONE FOR A VERY LONG TIME SO I HOPE YOU LIKE IT!  
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 **.**

 **A lot of people have been asking me to deal with what happened to Papyrus. Well, be careful what you wish for!  
**

 **In terms of which characters are swapped with which, I please don't expect this to be exactly like the official underswapped blog canon. Apparently Temmie is swapped with Frisk or Flowey or something? I'm really not sure where Asriel fits into that equation but I'm going to do my own thing here and it will definitely deviate quite a bit. I do have plans which make a lot more sense with this arrangement of characters so that's how I'm running things ;P**

 **Also I can't tell you guys how awesome it was to wake up to all your encouraging reviews yesterday morning. Your continued support is hugely motivating and I hope I can continue to meet all your standards ;D**

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WHATEVER CAN HAPPEN WILL

CHAPTER 12 - UNDERSWAP PT.2 - MEXICAN SANS-OFF

Alpha-timeline Alphys made a loud squeak and fell backwards off her stool.

She'd been up all night scribbling calculations between the Mew-Mew Kissie Cutie doodles in her notebooks to map the possible space-time trajectories Papyrus could've taken. Since his disappearance the previous day Papyrus' little icon on the screen had sat unmovingly on the same dot that Sans and Frisk's signal was coming from. She'd been in the middle of working on a way to get them all back when his icon had simply vanished with a little 'ping'.

Alphys had been so startled by the noise she'd lost her balance.

"Mmmwhat is it, Alphys darling?" Mettaton stirred on his bed and Toriel was starting to wake up beside him at the sudden commotion. Alphys found her feet while rubbing her definitely-bruised tail.

"P-P-Papyrus! H-He's gone!" Alphys stammered as she began to search the computer monitor for any sign of the grinning skull. She removed her glasses, cleaned them on the hem of her lab coat and put them back on. No change. She started to sweat.

"But he cannot be _gone_ , can he?" Toriel asked, padding over and leaning heavily on Alphys' work desk. "You said that this map shows every accessible version of our universe."

"I-I... well... yes! but... that t-tracker was never designed for this sort of thing." Alphys muttered as she started wringing her hands together. The calculations she'd spent all night on had gotten her nowhere. She was way, way out of her depth with this and now she'd messed everything up again. Losing Papyrus was her fault.

Alphys felt a strong pair of arms coil around her.

"This isn't your fault sweetie. You couldn't have known he'd activate the device." Mettaton's sensual, metallic voice said from behind her ear.

No. She should have known Papyrus of all monsters wouldn't understand the delicacy of the science he was dealing with. She should have been more careful. The responsibility for keeping him safe had been her's and she'd failed him. Vaguely, she wondered if Sans would kill her for this.

Unable to master her words, Alphys just shook her head side-to-side. She was such a screw up. She'd failed everyone. She still didn't even know what had happened to Undyne... and she'd never even gotten to tell the beautiful fish-monster how she really felt about her.

"My child..." Toriel whimpered as she too lowered herself to the cold, tiled floor.

Alphys wanted nothing more than to fast-travel to the Garbage Dump and hurl herself into the abyss like she'd contemplated so many times before. At least that way she wouldn't have to worry about failing everyone anymore.

With another 'ping' Alphys watched as the icon representing Frisk and Sans blipped to another dot. She blinked her sleep-deprived eyes. They were still... alive? Alphys had precious little processing power left after the past day's emotional onslaught and felt her eyelids drooping as Mettaton and Toriel gasped at what this new data entailed.

Alphys decided she'd keep herself alive long enough to save them, at least.

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Sans felt himself go catatonic as the alternate version of himself leapt out into the center to the room. He was wearing little floatie wings emblazoned with hearts around his upper arms and a headband that looked like he'd just found it in the trash. His blue scarf billowed heroically behind him.

"it's time to do 100 laps! while shouting about how great we are!" Alternate Sans bellowed with more enthusiasm than could possibly be contained in his stout frame.

"I-I'll try my best!" Undyne shouted from inside her trashcan.

Vicarious embarrassment felt like a physical lump in his chest cavity as Sans watched the two monsters rush off into Waterfall, hooting and hollering about how awesome they were.

Beside him, Frisk finally buckled under the force of her amusement and just started cracking up while trying not to drown on the floor. Sans felt like his brain had blue-screened.

"Who's there?!" Strong Alphys' voice suddenly called out, making Frisk cut off her laughter in a snort. Her eyes flicked up to meet Sans' as they both scrambled further behind the trash pile.

"IDENTIFY YOURSELF!" Alphys shouted again.

Sans could hear Alphys moving closer towards them over the low hum of an energy spear manifesting. He didn't want to have to contend with an angry Leader of the Royal Guard right now, especially after witnessing... whatever that just was. He grabbed Frisk's hand and pulled her quickly into a shortcut beside him without thinking.

"Whew, that was close!" Frisk gasped as they emerged into the alleyway behind Sans' house. He tottered a little with exhaustion from the long jump and slumped forwards into the snow before Frisk could try to catch him. "Sans!" She cried, but it sounded distant to him.

There was a soft clicking noise as the door to Sans' lab unlocked itself and opened. Sans felt his bifurcated soul break a little at the sight of Papyrus staring down at them in surprise. It wasn't _his_ Papyrus, but it was close enough to make blue tears jump to his eyesockets before he passed out.

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Sans woke up on his own lumpy couch to quiet music from the television and the more immediate sound of cooking coming from the kitchen. His first thought was that Frisk had RESET again and he was surprisingly relieved. After what had happened with Gaster, Sans had assumed that they'd never be able to restart the timeline again, which as good as it sounded was a lot more stressful in practice.

Being back at the beginning of a new timeline was comfortable and safe in a way that as fucked up as it was, was still better than the alternative.

A light hand brushed against his fibula and jolted him to full wakefulness. Frisk was there on the couch with him with his legs resting over top of her lap, staring at him with an expression of concern and... apology?

"HEY. AWAKE ALREADY?"

Sans didn't know how much more emotional trauma his soul could take as the same Papyrus he'd seen earlier outside his lab leaned out of the kitchen, balancing three plates of food on his arms. The lanky skeleton was wearing a very Sans-esque hoodie in a muted orange accompanied by long, baggy pants and comfy-looking sneakers. Sans crinkled his nose-ridge when he noticed the pack of monster-cigarettes peeking out of his pocket.

"YOU USED TOO MUCH OF YOUR MAGIC, ER- SANS." This Papryus chattered as he sat cross-legged in in front of the couch, trying not to draw attention to the verbal slip. "YOU NEED TO EAT SOMETHING AND REGAIN YOUR STRENGTH. THE HUMAN EXPLAINED WHAT HAPPENED. MORE OR LESS." Papyrus cocked his head at Frisk, who was definitely looking contrite.

"I didn't know what to do. And... I knew Papyrus would never hurt us." Frisk's fingers lingered on the bones of Sans' ankle, making him shiver and sit up more.

Sans had been about to say something when he noticed the unmistakably greasy scent of Grillby's burgers on the plates Papyrus was handing out. He couldn't stop a moan of pleasure as he stuffed one into his face whole and chewed it with an expression of absolute euphoria.

"it'sh okay, kid. Thish Papsh ish cool." Sans said through the 'burg. The alternate Papyrus was looking at him incredulously, like he'd just seen a Temmie solve a Rubik's Cube. Shrugging his shoulders, Papyrus took a bite of his own burger. _TIME TRAVEL SHIT_ , that shrug said.

Sans wiped his face off with his sleeve and leaned back against his armrest, tactfully pulling his leg out of Frisk's grasp.

"so you're the _me_ of this universe, huh?" Sans folded his arms behind his head and watched this swapped Papyrus watch him around a mouthful of 'burg. Papyrus cocked a brow.

"THIS IS _MY_ HOUSE, BUCKO. I'M THE ORIGINAL HERE." Papyrus smirked in a lackadaisical way and wiped his jaw off with his own sleeve.

Frisk was looking between them, a little anxious that they were about to have a Mexican Sans-off.

Sans had to stop himself from saying anything as the alternate Papyrus pulled out a rolled-up 'cig from his pack and lit it with a small spark of orange. With a sudden sensation of vertigo, Sans realized Papyrus was right. In this universe, Sans was just a swapped Papyrus who'd decided to crash the party.

 _i'd kill for some condiment right now._ He groaned internally.

Then, as if multiverse had picked this particular moment to start answering his prayers (better late than never), Papyrus pulled a six-pack of ketchup-bottles out of thin air. It was a little startling to see his own powers being used so gratuitously, but Sans figured that this Papyrus had nothing to hide from them.

Frisk politely excused herself to have a shower upstairs and it was only afterwards that Sans realized she hadn't even asked permission. Or where to find the craftily-hidden room. Papyrus seemed to notice as well as he finished and smothered his 'cig in an ashtray and cracked open a pair of bottles.

"STRANGE GIRL YOU'VE GOT THERE. EASY ON THE EYES, THOUGH." Papyrus leered at Frisk's backside as she retreated upstairs. Sans was glad he hadn't drunk anything yet or he would've sprayed it out through his nose-hole.

"its, uh... not that sort of thing." He blurted, suddenly feeling judged. "but don't you get any ideas." Sans clinked his bottle against Papyrus' and they both up-ended their drinks. Sans tried to covertly watch Papyrus as he chugged to make sure that he wouldn't be the one to let up first. However, their eyes met and the unspoken challenge was accepted.

They both slammed their empty bottles on the coffee-table at the same time. Sans grinned.

"YOU'RE ONE STRANGE SANS. YOU KNOW THAT?" Said Papyrus, already handing over a second bottle which Sans opened with his own blue magic, feeling like his Sans-hood was being questioned. He moved over to let Papyrus climb onto the couch as well.

"i've been told i'm pretty _sans_ sational." Sans grinned wider, measuring this Papyrus' reaction. He was rewarded as Papyrus groaned and dragged his fingerbones down his face.

"UUUUUUGH! I KNEW IT WAS TOO GOOD TO BE TRUE." Papyrus opened his bottle by swiping the cap off with his palm in a practiced motion. They clinked bottles again. Chugged. Slammed them down.

They both paused to listen for a moment as they heard a rising commotion from outside.

"run undyne! only 99 laps around the underground to go! and don't forget to tell us how great you are!" Sans recognized his own voice enthusiastically shouting as his doppelganger ran through the streets. A quick glance out the south-facing window showed a chubby Undyne running haggardly behind him.

"I'm -gasp- pretty cool! -heave- I guess!" The fish-monster shouted half-heartedly as she passed the house.

"again!" Other Sans shouted from way ahead. "and once we're done i'll treat you to my 'you're amazing' spaghetti!"

"Nooooooo-wheeze-ooooo..."

Sans and the alternate Papyrus shared a grin.

"MY BROTHER SURE IS COOL, HUH." Papyrus summoned two more packs of ketchup from the kitchen, already uncapping another pair. For the first time Sans began to worry that he'd be able to keep up with the taller skeleton.

"you have no idea, buddy." Sans said quietly, working very hard to keep his grinning mask in place.

By the time they'd finished off the second pack of monster-alcohol Sans decided he was definitely drunk. He wondered what was taking Frisk so long but he had bigger skeletons to fry. Papyrus was looking it him from across the couch with a determined set to his jaw. At least his eyesockets were starting to look a little bleary as well, Sans thought.

"SO THEN YOU PUNCHED GASTER IN THE FACE? OR WAS THAT EVIL SANS?" Papyrus slurred as he took another gulp of his ketchup. The mess of haphazardly discarded bottles around the couch would've had San's Papyrus screeching at the top of his lungs. Sans subdued another wave of grief as he finished off his drink a little more aggressively than was necessary and uncapped a new one.

"evil sans. gaster's too tall to punch in the face." Sans chuckled, now practically laying horizontally on the couch.

"FOR YOU, MAYBE." Alternate Papyrus jabbed him playfully with the toe of his sneaker.

"didn't have to _reach_ too far for that joke, did'ya?" Sans rolled his pupils dramatically. "but don't let me sell ya _short_."

That one actually earned him a chuckle which was quickly turned into a cough. Papyrus was unmistakably smiling and _hating it_.

"but yeah. the guy had it coming. you wouldn't believe how that sans treated his papyrus. an' besides... he said he'd seen _my_ paps. had 'ta make him talk." Sans rumbled, downing the bottle in one shot. He'd lost track of which bottles were even his or how many he'd had. He'd stopped caring a while ago.

"YOUR PAPYRUS? HE FOLLOWED YOU?" The alternate Papyrus leaned forward, making the hood of his jacket hide his face in shadow.

Sans tried to backpedal but it was too late. The idea of Papyrus being trapped in that tower as it collapsed was too much to bear. Even if he'd survived, he'd have been all alone as the universe broke into nothing around him. Sans wondered if Papyrus had called for his big brother as he died.

It was all too much. Sans moaned pathetically and leaned forwards to hold his head in his hands. Unwanted tears were pooling in eyesockets.

"i... i really fucked up. i wasn't there for him when he -hic- needed me." Sans cringed as he felt this strangely mature Papyrus' hand on his shoulder. "i dont know what i'm gonna do... now that we can't reset. i'll never -hic- see 'im again." He started sobbing openly now into his hands. However, the tears kept slipping through his boney digits and onto his shorts. Papyrus' sympathetic fingers dug into Sans' hoodie. Being aware of the timelines like Sans was, this Papyrus knew the pain of losing a brother all too well.

"'M SORRY, BUDDY." Papyrus said quietly as Sans cried himself out. It was such a fucked up situation, bearing his soul to an alternate version of himself who was also Papyrus. But he'd drunk too much and couldn't seem to stop himself.

Eventually, Sans finished and the silence lengthened in the dark house. When Sans looked up Papyrus had a distantly pensive expression on his face, illuminated only by the streetlamps through the window. He longed to ask the long-boned skeleton what he was thinking, but was afraid of the tired intelligence in those dark eyesockets.

"YOU SHOULD SLEEP, SANS. 'S BEEN A LONG DAY." Papyrus stood uncertainly, still obviously drunk and helped Sans to his feet. Together they tottered up the stairs into Papyrus' room (the one furthest from the stairs) and Papyrus offered Sans his bed for the night. His Sans wouldn't find it suspicious at all if he were to fall asleep on the couch. Even if he would probably yell at him tomorrow for it.

"thanks, paps." Sans muttered, feeling nauseous and exhausted as he flopped onto the familiar mattress.

"G'NIGHT SANS." The alternate Papyrus lingered in the doorway, obviously having something else to say. Sans rolled over on the bed to face him. "I'M SORRY 'BOUT YOUR PAPYRUS. BUT PLEASE, YOU NEED TO LEAVE TOMORROW. I DON'T WANT YOUR PROBLEMS HURTING ANYONE I LOVE, CAPICHE?"

Sans locked eyesockets with the drowzy-looking skeleton.

"yeah. tomorrow." He promised as Papyrus closed the door behind him. Sans wanted nothing more than to leave this topsy-turvy universe in peace, but he knew that even if they did, Gaster wouldn't. He'd be after whatever passed for Frisk's soul here and they couldn't leave until they denied him.

Sans turned onto his back and tried to will himself to sleep. Moments ago he'd been completely exhausted, but now he just felt wired and more than a little nauseous. How was Gaster going to try to hurt them this time? If the Prince had taken Frisk's place in this universe, what was driving him towards the capital? Did he somehow possess a human soul? Where did that put Frisk in this picture? And Chara?

Thoughts churned round and round in his skull like the trash tornado in the corner of the room, directionless.

He felt more than saw Frisk when she appeared in the space where his shortcut (or rather, Papyrus' shortcut) to the Hotlands was. He let out a long sigh and resigned himself to his insomnia.

"where've you been?" Sans slurred and propped himself up on his elbows. All he could see of Frisk was the blue circle of her stolen eye in the blackness of his room, but she confidently walked past the gag-treadmill, fished a battery out of his drawer and activated the flash-light lamp.

She was frowning.

 _great._

"I thought you two were going to fall asleep in each other's arms at that rate." She said, lowering herself onto the corner of the mattress. "Meanwhile, _I've_ been making sure this universe doesn't blow up in our faces like the last one did."

Sans felt his cheekbones warm in indignation. He knew she was right, of course, but he wasn't in the mood for rational thought. His skull felt like someone had stuffed it with wool socks.

"and?"

"And nothing." Frisk actually sounded annoyed that nothing had gone horrifically wrong. "In this universe, Asriel is playing my role, except he's not trying to escape from the Underground. It's some sort of weird Boss-Monster-Bar-Mitzvah to start at the Ruins and fight your way through your subjects on your way to usurp your parent."

Sans didn't ask what a 'Bar Mitzvah' was.

With a yawn Frisk stretched so expansively it made her joints pop and she settled half-on-half-off the bed, looking peeved and as restless as Sans felt. "Thing is, Asriel still only has a monster soul so he couldn't be the one Gaster will go after. I snuck into the True Lab as Asriel fought the Amalgamates once Al-er-Undyne gave up on running laps with 'Jog Boy'. I couldn't even sense _her_ in there with him."

"chara's missing too?" _don't mention jog boy_ "but your soul must be around here somewhere, an' i don't mean the one in my chest." Sans tried to make light of their bizarre situation but it fell flat. He decided to fall flat as well by putting his hands in his pockets and stare up at the familiar ceiling.

Sans was very aware of Frisk's gaze boring a hole into his right temple. He could feel her tension through their linked soul, but didn't comment on it. Was she still hung up about what had happened earlier when they'd been hugging it out on that flower-island? As he felt her hand reach out and rub against the top of his skull he decided that yes. Yes she was.

"Aren't you curious?" Frisk asked. Her fingers were making lazy circles on his suddenly-sweaty crown. He was way too drunk for this.

"'bout what?" Sans said, pretending like his thoughts hadn't fallen straight into the gutter. If he'd been sober he would probably have just moved away as he had downstairs but he was in serious need of some comforting right now, and those soft fingers felt nice. Frisk considered her words for a moment before responding.

"The timeline where we were together." She pulled herself fully onto the bed and shifted so her head was lying adjacent to his, only she was perpendicular to him. Her fingers moved down to the base of his skull, tickling his sensitive mastoid process. He squirmed a little, but didn't move away.

"heh, you are _frisky_ today." Sans tried to hide his growing discomfort with a pun, but the feelings her bubbling laugh provoked in him only made him more unsure of himself. His relationship with this girl- a woman now, clearly was so irrevocably screwed up he didn't even know where to start. They'd been friends, mortal enemies, adopted family and apparently even lovers. She'd killed his brother. She'd spared his brother. She'd killed _him_ , and she'd spared him too only to receive the dunking of her life.

Frisk cut his runaway train of thought short by lithely moving over to straddle him. "So what if I am?" She practically purred as her half-lidded eyes caught the low light. Despite the fact that he was literally a skeleton, Sans did have quite a bit of girth to him and the way she was poised right now meant she was practically sitting on his magical belly.

Sans had no idea how to respond to any of this. It was obvious that Frisk wanted more from him than he was willing to give, but Sans really didn't know how much that was right now. The curtain of her hair bathed her face in soft shadow, hiding the nervous pinch of her lips that anyone who didn't know Frisk would mistake for a pout.

But he did know Frisk. She was waiting for him to make the first move.

Sans leaned forward and pressed his teeth against those nervous lips, a little jolt of blue magic jumping between them. It tingled. Sans blamed the monster-alcohol as his fingers found their way to the back of Frisk's neck and pulled her in for a deeper kiss. She gasped a little at his change of heart, a soft little sound that made Sans' grin widen. He pulled her off him and reversed their positions so he was the one on top.

"Now who's frisky?" Frisk smiled as she admired him from below. This felt so weird. This was _Frisk_ he was kissing. But the way her fingers traveled down his cervical vertebrae in all the right places told him that she'd obviously been with him before. It hadn't been _him_ , but he and that Sans were still the same monster. They'd both walked the line between loving and hating this strange, captivating human.

As he kissed her again and wound his fingers in her thick hair he was glad he'd chosen this side of the line. If he tried not to think about it their circumstances, he could imagine that they were at home in his own bedroom. Frisk made it easier for him by arching up towards him in pleasure and making that little noise again. He sent little kisses of magic down her neck and to the softness of her shoulder. Then he just nuzzled into the crook of her neck for a moment and just let the feeling of her wash over him. She kissed the corner of his jaw, seeming impatient.

Sans let her hands guide his mouth back to hers and the electrifying discharges of their shared magic overwhelmed him again. He hadn't even noticed how tense he'd been until it all started uncoiling from him in her arms. He shuddered as his body responded to hers, evoking instinctual magic he hadn't felt in a long, long time. Too long. The lilting grin Sans found on Frisk's lips as he kissed her again told him that she'd noticed too.

Frisk unzipped the front of his hoodie without breaking off her kisses but Sans stopped her from pulling it off entirely. He wasn't super happy about the way he looked underneath the obscuring fabric and she didn't push him. Despite her ravenous kisses, Sans could tell she was being very, very careful. Clearly she was aware of his insecurities as her fingers slipped inside the hoodie and only skimmed his softer parts before finding their way to his shoulder blades where they grasped needfully, pulling him further down onto her.

Boney fingers tensed in Frisk's hair as her thumb hooked into the interior of one of his ribs where it met his spine. She knew him too well. The smooth, jelly-like consistency of his magical flesh would give way under sustained pressure and allow her access to any part of him, if she wanted to access it. For now, though, she seemed content with kissing him and making lazy, stimulating circles with her thumb as he struggled not to become a complete mess.

He'd had no idea he'd needed this release this much. His mind kept trying to over-analyze what was happening, trying to remember the exact reasons why this shouldn't be happening. But then Frisk would kiss him again and slip her fingers somewhere he hadn't even known he'd liked and all those thoughts would fly away. He felt utterly at peace.

Eventually, Sans had to call it quits as his limited stamina depleted to the point where even holding himself up with his arms was uncomfortable. He gave Frisk one long, parting kiss and felt his magic call out to hers one last time before he drew back to lay beside her on the mattress, panting.

 _well that was... something._

Frisk said nothing, only shifted her body so she was laying right up against him. With his magic, Sans flicked off the light.

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* * *

 **This chapter was very interesting to write, since it was really difficult to balance exactly where the line between Sans-ness and Papyrus-ness landed in UF!Paps. And what better way to bond with your alternate time self than with some good food, some bad jokes and a human girl who definitely has her own agenda. ;) That last scene with Frisk and Sans was also a hell of a lot of fun to write and a long time coming. I always imagined that Sans would be a little self-conscious about the fact that he was a chubby skeleton but would simply laugh it off whenever somebody brought it up. As a kid he probably would've been thin like his dad and brother, but the depression of finding himself caught in a hellish time-loop for the rest of eternity led him to some comfort food and left him with no motivation to maintain his appearance or exercise. At first I'd actually assumed that was why Sans kept that treadmill in his room, perhaps as some discarded notion of getting back in shape.  
**

 **Either way, hope you guys enjoyed this chapter! And sorry for tacking on the second half so belatedly. I really wanted to get the more character-based parts grouped together so the plot can proceed next chapter without needing to suddenly change tones for the bedroom scene.**

 **And yes US!Papyrus would call them 'cigs.**

 **Expect the next chapter sometime this weekend!**


	13. Chapter 13- UNDERSWAP PT3

**Howdy! This chapter's a bit of a mixed bag. It's got some happy bits and some not-so-great ones, but I think you dear readers have probably gotten used to this by now in this story heheh. I hope you like it!**

 **So last chapter we got to see a more intimate side of Sans and Frisk. I found a great image on tumblr by 'zeefsterart' of Sans in the style of another artist called 'siins'. (except my idea of Sans doesn't have eyebrows)**

 **It can be found here: zeefsterart. tumblr (.com)/ po st/ 134427685408/ siins-sans-is-a-gigantic-teddy-bear-1010-would**

 **^Just make sure you take the .com out of the brackets and smooth out the spaces. Why must FF be so silly?^**

 **As I mentioned way back in Chapter 1 I imagine Sans as being proportionate to an adult human (a bit less than 6ft). He'd also pretty wide and even more so with his hoodie so he seems bigger than he actually is. Hope that clears some things up!**

 **WARNING: Thoughts of suicide in this chapter.  
**

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* * *

WHATEVER CAN HAPPEN WILL

CHAPTER 13- UNDERSWAP PT.3 - COOKING WITH A KILLER SKELETON

{{{{{The room came into view slowly and in pieces. First the shadow, then the bands of golden light that cut the blackness like a knife and illuminated the right side of his body in high contrast. The marble floor polished to a shine beneath his slippered feet. Tiny motes of dust that swirled between the dark stone pillars that reached up to infinity overhead. From beyond the gothic-styled stained-glass windows Sans could hear the sounds of birds singing, he could smell flowers blooming.

The child stepped out of the abyss of shadow cast by one of the pillars where they had stood all along, simply waiting for the rest of the world to appear and give them context. Sans felt cold rage stirring in his rib cage as they hefted the blood-spattered knife in their hand, flipping it carelessly in the air and catching it again. Their wide smile glittered white in the dazzling light yet their eyes remained like daubs of black shadow.

In a blaze of blue fire Sans felt his magic come to life in his left eyesocket, burning with Judgement.

"lets just get this over with." He said simply and without warning exploded into action. The skeleton sent everything he could at the child in that first moment of the fight, firing alternating waves of bones, blasters and blue magic in one last desperate attempt to stop them. He had finally come to realize this _abomination_ wouldn't just give up, wouldn't just RESET this timeline. He would never see his brother again.

Unless he could turn them back.

True fear crept into Sans' soul as the child landed lithely on the ground completely unscathed after his onslaught. The sickly crimson of their soul throbbed over the center of their chest, illuminating their face from below in its murderous glow.

He had to make them RESET.

The child lunged at him then and he warped through the one of the many shortcuts that riddled the space here. They were the reason he'd chosen this specific room to stand against her.

No surprise touched the child's face as they passed through the space he'd just occupied and quickly transitioned into evasive maneuvers as he tried to trip them up with a stream of bones that carved through the pristine floor and left ragged gouges behind them.

They'd both done this too many times to count. Would this be the time when he finally failed? Fear chilled his bones.

The dance continued.

Sans thought of his friends as the fight dragged on, calling upon their memories to bolster his flagging strength. He slammed the child into the walls and floor and pillars with everything he had, his grin quirking upwards vengefully whenever he could cut her with one of his attacks.

But it wouldn't be enough. Not this time. Despair coiled around his spine as he realized that he'd become predictable.

He offered them mercy. They denied, the clever child.

Sweating profusely, Sans tried his best not to slouch as the fight eventually settled into a lull. At least the _freak_ was panting heavily as well, he thought numbly.

"if you can survive this, then i'll show you my special attack." Sans grinned viciously as he gathered the final dregs of his magic. His fingers and toes felt distant and when he rubbed his fingers together in his pockets he was terrified to discover they were _melting_.

He had to finish this. Now.

A blue inferno incinerated all conscious thought as he focused everything he had on killing the child. He wouldn't be the weak link in the chain of Sans' to break! Not him! He'd suffered too much to receive that final indignity.

His hand was a blur as he slammed the child into waiting phalanxes of bone and made them fall towards him through a gauntlet of death that put his brother's trap-gauntlet to absolute shame. He blipped through space to follow the child as they twisted and bent in the air, avoiding everything.

Screaming from the exertion, Sans summoned more blasters than he'd ever dared before. He sent them spinning in a roulette of hyperdeath that forced the child into a tight spiral, scrambling just ahead of the deadly beams which caught the back of their legs more often than not.

His magic ran out in an agonizing jolt that shook him from crown to coccyx and it was only through sheer determination that he didn't disintegrate into dust right then and there. The pain of existing was _excruciating_. But he had to win. _He had to._

The smile on the child's face was exultant as they watched him with eyes gone wide. She'd never survived that last attack before. The bright light streaming through the windows was painful on Sans' eyesockets as he struggled to initiate his next turn.

His last attack, if you could even call it that, was pure desperation. He just stood there, willing to wait until the end of time if he had to. They _would_ RESET. He was going to see his brother again.

But he was so, so tired.

Alarms rang in Sans' skull as his vision dimmed. The child was staring at him with an expression of rapture, the shadow of their eyes replaced with a luminous red as they anticipated their victory.

 _Wake up, Sans!_

Distantly aware that he was about to die, Sans couldn't stop his consciousness from flickering out.

 _Wake up!_

He heard a voice distantly but couldn't recognize it. He wanted to wake up, he really did. He could feel the child inching towards him carefully, knife raised.

 _Sans!_

His pupils lit up just in time to see the knife descending. Space-time twisted around him abruptly as he dodged on instinct. He dodged at the very last second, he was-

He didn't expect the second strike.

.}}}}}

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Sans shot bolt-upright in bed with a strangled shout. Something was holding onto his shoulders and without thinking he struck out to knock the weight away from him. The back of his hand connected solidly with whatever it was and it released him.

Suddenly off-balance, he tumbled to the floor in a pile.

Feeling trapped, he quickly scrambled towards the furthest wall and pressed his back to it before coiling up in a fetal position. His whole body was shaking and it was only belatedly that he realized that it was because he was sobbing uncontrollably.

"S-Sans?" A quiet voice came from the direction of the bed.

Slowly, slowly, Sans uncurled himself enough to look towards the source of the familiar voice.

 _frisk._

The girl was on her hands and knees on the mattress, pressing one palm to her cheek which seemed very pink and was starting to puff up like she'd been hit. There were tears in her eyes as she stared down at him with an expression that was a quagmire of worry, shame, pain and fear. A wave of embarrassment rolled over him.

Something in the room was illuminating everything in a harsh, electric blue that was making shadows dance like there was something hiding in them. It was only when Sans felt the searing pain on the inside of his skull that he realized it was the light of his own magic burning in response to the perceived threat.

 _it was a dream._

 _just a dream._

Taking deep, shuddering breaths Sans slowly clamped down on his racing emotions and pushed them down into his subconscious where they belonged. The process took a few minutes but eventually the blue light dimmed to nothing. Neither of them moved an inch towards the other.

"I'm... gonna turn the light on, okay?" Frisk said and Sans nodded meekly in response but then he realized that she couldn't see him in the darkness and he gave a weak, affirmative grunt. He listened as her soft footsteps padded across the carpet and she clicked on the flashlight-lamp. In the low light Sans could clearly see the angry bruise spreading on her left cheek.

"did i do that?" Sans asked quietly, his pupils fixated on the red-purple splotch. Frisk's hand shot up to cover the bruise and she turned her face away.

"It's- It's okay. You didn't mean it. You were having a nightmare." Frisk whispered, eyes staring into the middle-distance.

Sans felt shame flood his system as he forced himself to sit up against the wall and organize his limbs beneath him. He felt like he'd just run a mile.

"is'not okay. i hit you." Sans carefully pushed himself to standing using the wall as a support. As he approached Frisk he discovered he'd lost one of his slippers at some point. His hand reached out to her, hesitated, dropped. Her eyes were so wide and beautiful and sad. Sans wanted to throw himself out the window.

Frisk shook her head and gave him a sad smile despite her puffy cheek. "Everything's so messed up." Fresh tears pooled in the corners of her eyes. "I'd forgotten how much the nightmares bothered you at first. Should've been more careful... but I probably deserved this, huh?"

Sans' eyesockets blinked in confusion. How was this _her_ fault? He was the one who'd hit her. Or was she referring to the nightmare? That had been Chara, not Frisk who'd killed him so long ago.

As if following his line of thought, Frisk's eyes met his. "If it makes any difference, watching Chara kill you gave me the strength to take control again. I RESET the second you fell." Her painful smile widened by a degree.

Sans had never known that.

"i... need to get some air. will you be okay here?" Sans couldn't bring his voice above a whisper. He'd never been a claustrophobic monster, but right now the walls of his room ( _not_ his room, he remembered) seemed to be closing in at an alarming rate.

Frisk nodded and used the hand which wasn't covering her cheek to touch his sleeve. Her smile only faltered a little when he flinched without meaning to.

"Yeah. I think I'll get some air too. Call me if you need me?" Frisk picked her cellphone up off the dresser top and texted him her number.

Sans felt his own phone vibrate and he nodded, unable to speak.

With a quiet click the bedroom door closed behind him as he stepped out onto the upstairs landing of (not) his house. He tried not to wake the Papyrus snoozing spread-eagled on the couch but as he moved to open the front door he thought he could feel his alternate brother's gaze on him. Maybe it was just his imagination.

The slight dimming of the Underground's magical "sky" told him it was "night" as Sans stepped outside. Nobody was around at this hour and Sans took the moment of solitude to press his palms into his eyesockets to alleviate some of the built-up pressure there. It didn't help much. The memories of the night before with Frisk danced in his mind's eye: The tingling sensation of their kisses and the pleased smile on her lips as she'd showed him some of the ways she knew to pleasure him. It was all tainted now. He'd ruined it.

Why had he ever thought they could be together? He didn't deserve her love, or anyone's. He'd failed everyone time and time again. Eventually he'd make a mistake and Gaster would get the last soul he needed to break the Barrier and send everything and everyone into the void with him.

There was still one last thing that niggled at him, though. It was the thought that Frisk had RESET after beating him that somehow kept his hope alive as it threatened to extinguish forever. There had never been a timeline where Chara had actually _won_. Despite all the heartbreak and suffering he'd personally gone through, in a funny way it was his friendship with Frisk that had ultimately triumphed over Chara. The good times had against all odds prevailed against everything else.

Monsterkind had made it to the Surface, but Chara never had.

As Sans walked off into the dim flurry towards Waterfall he was feeling just a little bit better.

.

.

The caverns in this universe were exactly like the ones Sans was used to, before Frisk had started muddling everything up with Gaster's help. He nodded to a passing Temmie as he meandered through the room with all the glowing mushrooms and reflected on how the unassuming and bizarre Temmies apparently existed outside the normal constraints of timelines and universes.

Then again, no one could actually recall when they'd appeared in the Underground. One day they'd just sort of... been there. Nobody had ever questioned it because who else were you supposed to sell your useless junk to? Maybe they'd already been living here before monsterkind had ever set foot in the Underground.

By the time Sans reached Hotland his negative emotions had abated to a tolerable level. The memory of the nightmare and his guilt at hurting Frisk still clung to him like old spiderwebs, but he could manage it. He'd find a way to go on, even knowing that his brother was gone forever.

Maybe, if they ever defeated Gaster he could join his brother again.

Sans recognized the suicidal thought for what it was but it too was something he could manage. He shrugged deeper into his hoodie as the hulking, white form of Al- (wait, no)Undyne's Lab appeared in the distance through the super-heated air, the wavy heat making the massive white dome appear to shiver at his approach.

Getting closer, Sans could hear voices and music coming from the lab, and he could feel a deep, wubbing baseline through the soles of his feet. He'd borrowed a pair of Alternate Sans' blue battle-boots rather than spend any more awkward time with Frisk in search of his missing slipper but now he was regretting it, since they looked ridiculous in contrast to his regular attire.

Suddenly, there was a sound like rustling leaves from over Sans' shoulder that made him spin around in alarm.

But the plateau was empty.

 _huh_.

Sans had been about to go investigate when the front door of the Lab slammed open, making him jump nearly out of his borrowed boots.

"SANS! You're late!" Muscular-Alphys roared at him from the doorway and in one fluid motion leaped towards him, hefted him by his middle and pulled him inside. The music inside was deafening but at least it covered up his surprised yelp as he was deposited unceremoniously on a couch between Nervous-Undyne and Chill-Papyrus who gave him a long-suffering grin.

The lab was full of monsters Sans recognized yet didn't- they were all reversed versions of their usual selves. It seemed to be some sort of celebration that half the underworld was attending since the bottom level of the Lab was packed wall-to-wall with monsters who were all laughing, dancing and having a great time. Over by the furthest wall Sans was surprised to notice a makeshift bar had even been erected and Grillby, who now had six arms and four pairs of spectacles was passing out cups of flaming spiders.

 _oh, now that's a bit far, isn't it?_

"You made it, brah!" The robot behind the DJ-booth shouted at Sans over his own music as his hands scratched his records necessarily. Sans was having trouble matching the white-and-blue robot in his backwards baseball cap with anyone he knew from his own universe. The fact that the robot's chassis was dented in multiple spots and he had wires hanging loose didn't help the matter.

It was only when he noticed Mettaton in his ghost form dancing nervously on their own in the very corner of the dance floor that he figured it out.

"hey, napsta." Sans said, forcing enthusiasm. Had they mistook him for the Sans from this universe? Napstaton nodded cockily at him and then turned back to his mixing. The current song was a weird re-hash of Death By Glamour but more industrial-sounding and with a baseline that made Sans' bones rattle.

"FORGET YOUR CAPE, SANS?" Alternate Papyrus was grinning casually but his eyes were dancing with amusement. _damn him._ Seeing a new twinkle in those dark sockets at his annoyance Sans desperately hoped that this Papyrus hadn't tried to look in on him and Frisk last night. That would reach some unprecedented levels of awkward.

"uh.. yeah. it just sorta... _capered_ off?" Sans winced internally at the awful pun but the way Alternate Paps cringed made it worthwhile. Beside him, Undyne groaned minutely.

Sans recalled how at this point in the timeline Undyne would have recently revealed her secret regarding the amalgamations which was probably what this party was all about. Papyrus would probably say something kind and encouraging to her, Sans realized. Then he tried to think about how Papyrus would phrase it and moaned internally.

"w-wowie, undyne. you did a really good thing by sendin' everyone's family home. i guess my- uh, super amazing training worked after all?" Sans could feel himself blushing. He didn't like complimenting himself (especially since he was taking credit for another Sans' actions) but they'd get suspicious if he didn't. At least Undyne perked up a little at the praise.

"OF COURSE IT DID. YOU'RE THE BEST, BRO." Alternate Papyrus's grin was practically off-the-charts.

Sans extracted himself from the couch with effort and bent himself into a Papyrus-like stance of self-appreciation.

"i am. the great sans. after all." He angled himself so that only Papyrus could see the brief warning flash of blue in his eyesocket. The bastard just grinned wider at it, reaching critical-meltdown levels of smirk. "and i shall, uh, regale you all with stories of my greatness. but first i gotta use the bathroom."

Sans got two steps towards the lab exit before he felt a strong, clawed hand close on his arm. He gulped.

The music stopped abruptly as tension filled the room. With a wet gloop one of the amalgamates which Sans hadn't noticed before dropped a limb on the floor and then tried to reattach it nonchalantly.

"NOT SO FAST, short stuff." Alphys said, her grip like iron. Trying to maintain some semblance of composure, Sans gave her a pathetic attempt at a grin. Was she on to him? He could feel the sweat appearing on his forehead but there was nothing he could do about it. Alphys' single eye pinned him in place like a spear.

The impulse to teleport away was overpowering but that was probably the worst thing he could do in this situation, Sans decided.

"You promised Undyne some of your 'you're not a huge liar' spaghetti. You wouldn't DREAM of backing out on her, would you?" Alphys' lips had curled back into a predatory smile that would brook no argument.

"s-spaghetti?" Sans managed. He was sure he could hear his humerus bending between her claws. Belatedly he tacked on a little "nyeh heh heh?"

Oh, she was definitely onto the fact that something was amiss with him. Alphys was an analytical type no matter what universe she was occupying, apparently. She must make an extremely effective captain of the Royal Guard. Sans wondered how Prince Asriel had ever made it past her.

"you're right! let's kill... some pasta?" Sans had spied on enough of of his brother's cooking lessons to get a general idea of Undyne's philosophy regarding cuisine but he'd always gotten bored by the time they went beyond laying out the initial ingredients. He kicked himself internally for his laziness.

The music started up again at a slightly-less-earbone-shredding volume this time.

He yelped again as Alphys picked him up, leaped to the second floor, cleared off Undyne's work bench by kicking nearly everything to the ground and then set him in front of it. She pulled a crumpled-up box of noodles and an armful of tomatoes and garlic from her pockets to Sans' amazement.

"GRILLBY!" Alyphs roared and Sans watched the eight-limbed flame-monster orchestrate a team of spiders which descended from the ceiling with an NTT-brand oven. Sans looked between the ingredients laid out before him and tried to remember everything he could about cooking. It wasn't much. At least he knew how to make 'dogs and he hoped to God that the same principle applied here.

"shouldn't there be, i dunno, water?" Sans asked, looking skeptically up at the menacing dinosaur-monster. Her good eye crinkled suspiciously. _shit!_

"wowie?" He added.

"Water?" Alphys gave an irritated flick of her tail and tilted her head to the side. "What's gotten into you, Sans?"

Papyrus and Undyne had just mounted the stairs the normal way and were keeping well back from the impromptu kitchen. The alternate Papyrus seemed to be staring at Alphys very intently and Sans could see the tension in his hunched shoulders. He didn't know what would happen if Alphys decided he was an impostor but Sans knew it probably wouldn't be good. It would probably end with him in approximately 206 separate pieces.

Sans tried to make up for lost points by using his Papyrus-pose again by sticking his chest out, shoulders back and jaw high in the air. He channeled all his limited snootiness into a single "nyeh heh heh heh!". He felt ridiculous.

"i. the great sans. am going to go where no pasta chef has ever gone before." He turned to the crowd which had formed around them (also keeping well out of harm's way). "i am going to try. a new technique to defeat. spaghetti?"

Sans couldn't help but feel a little impressed with himself as he turned dramatically, found a water faucet on Undyne's lab bench and filled a large, clean-looking beaker about a third of the way. Undyne didn't look worried about his choice of pot so he figured it hadn't been used for anything nasty.

Next, he turned the stove on high-but-not-too-high and let the water begin to boil. Alphys' eye was still watching him as he bustled around the kitchen but she seemed more intrigued than suspicious. Good thing Al was always a sucker for learning new things.

Sans contemplated the vegetables. The round, slightly-bruised tomatoes seemed to say their final prayers as he stood over them, fist raised to smash them like he'd seen Papyrus do. He brought his fist down as hard as he could and one of the tomatoes squelched a little before rebounding back to normal. He had dealt it 1 damage. Alphys stiffened behind him in confusion and he could have sworn Papyrus gave a snort of laughter which was quickly turned into an awkward cough.

"n-new technique, remember? gotta, uh, show 'em who's boss first." Sans muttered with as much conviction as he could muster. He stepped back from the workbench and sent Undyne a silent apology.

Raising his left hand he summoned a line of bones and willed them to wicked sharpness as they floated and tumbled above the doomed tomatoes and a single clove of garlic. The crowd took in a sharp breath of excitement. He unleashed his attack and the flurry of bladed bones slammed into the bench and diced the tomatoes in short order, dicing up much of the bench along with it.

Sans felt everyone's impressed stares crawling on his back as he scooped the decimated vegetables into another beaker which he set on a lower heat beside the first. Then he added some pasta to the now-boiling water and stepped back.

"now for my special attack." He muttered so only he could hear. He grinned and waited.

Alphys grew more and more tense as the minute mark passed and he still hadn't moved. The crowd seemed enthralled and Sans simply felt exhausted. It was such a hassle being Papyrus, he didn't know how his brother could handle it.

 _handled it. he's dead, remember?_

Sans shook his head minutely to clear away the ugly thought. He would grieve when he wasn't on trial.

Two minutes passed and Sans tested the pasta with a mixing rod. It was softer now and would bend if he pressed on it. That was supposed to happen, right? He stirred the sauce as well and added some salt and pepper which Grillby handed over at his request.

Three minutes and Alphys looked like she was about to explode. The Leader of the Royal Guard has turned about as red as the sauce Sans was stirring casually.

Four minutes.

"AAAAAAGH! I CAN'T TAKE IT ANYMORE!" Alphys hit the stovetop with both fists and both beakers went flying into the air. All eyes followed them up, up, up as they seemed to hover in slow-motion. Sans saw his chance and seized it.

Faster than the eye could follow he teleported over to a stack of plates he'd seen downstairs, grabbed them and blipped back into his original place in the next instant. With a muted blue flash of his eyesocket he grabbed the slowly-descending pasta and sauce in a field of his magic and guided it to the dozen-or-so plates he'd fanned out before him. As his magic took hold, however, he could've sworn he felt the tingle of his magic mingling with someone else's. He could feel the smugness in the orange-tasting magic prod him in good humor as it dissipated.

There was a shocked moment of surprise as everyone's mind caught up to what they'd just witnessed then a thunderous applause of clapping tentacles, claws and other appendages broke loose. The Royal GuardCats yowled their pleasure and rushed up to nuzzle Sans with their furry heads. Sans felt himself blush a deep indigo in embarrassment.

At least the pasta had been a resounding success that even Alphys couldn't deny despite her protests about him not being aggressive enough. Undyne had accepted hers with a nervous nod and stared at the plate for a long moment before finally mustering the courage to taste it. When she did, she couldn't stop the smile that appeared on her thin, expressive lips.

"W-wow Sans. This is really good!" Undyne praised him and Sans couldn't help but feel a little proud of himself. It had been so, so long since he'd actually made something for someone else and it felt good. He wondered if he should make Frisk something to apologize for the way he'd acted that morning.

However, the warm, fuzzy moment was not to last. Sans felt his cell buzzing in his pocket and he politely excused himself to answer it by the lab entrance door.

"that you, kid?" Sans asked but was immediately bowled over by Frisk's whispered shouting.

"Sans! What're you doing!? You need to get out of there right n-"

The front door of the Lab burst open so hard that it practically came off his hinges. Sans was distantly aware of Frisk still talking on his phone but his attention was completely captured by the blue-faced, panting skeleton that had appeared in the threshold right in front of him.

The two of them locked stares for a confused moment that seemed to drag on like a snail-race. Alternate Sans' expression shifted from enthusiastic exhaustion through enthusiastic surprise, enthusiastic confusion, more-enthusiastic amusement and back to the confusion again. Then the alternate Sans actually smiled. The sincerity in that beaming grin practically knocked the wind out of Sans, it was just so completely _Papyrus_.

Sans took a step backwards into a shortcut on instinct and teleported. He found himself suddenly on the other side of the Hotland main plateau behind a boulder and fell to his knees.

 _that was too close_. He thought, knowing that if he'd had a heart it would be pounding right out of his chest. From across the open room he could hear his alternate self shout in surprise at his sudden disappearance. He watched the other Sans lean out the doorway with an enthusiastically dumbfounded expression and look around wildly for his doppelganger but then he seemed to remember something and ducked back inside.

"everyone! there's been an emergency!" Sans heard his own muffled voice only because it was turned up to maximum volume. He could hear Alphys shout something back at him and there was some confused yelling before Alternate Sans appeared outside again with the alternate Papyrus, Undyne, Alphys and even Napstaton though the latter was limping and sparking. It occurred to Sans that Asriel had probably pummeled the robot pretty well during their dramatic fight to reach the King.

Alternate Sans took one last look around the plateau before herding his friends and brother into the elevator at the northern edge of the room.

"-Sans! Sans are you there?!" The speaker on Sans' phone are shouting at him and it took him a moment to realize he was still on the line with Frisk.

"uh, yeah. yeah i'm here. sorry." He said, bringing the phone back to his skull as he tried to process everything at once.

"I think Flowey's making his move. You need to get to the Throne Room _now_." Frisk's voice sounded uncharacteristically emotional and something about it sent up little red flags for him. He never knew exactly what happened with Frisk after Flowey stole all their souls but he knew it probably wasn't good.

"meet you there, okay?"

But the line had already gone dead.

That wasn't a good sign at all. Sans stood using the boulder for support and looked up to the top of the Hotland cavern where the NTT resort glittered at the threshold of the Core. This universe was a good one, and he vowed not to fail them like he had the last one.

Next, he searched around for a shortcut to the Throne Room and leaped through it.

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 **Hope you all enjoyed 'Cooking with a Killer Skeleton'! I knew I wanted to work something like this into the Underswap arc at some point and i"m happy with how it turned out. Also you gotta give poor Sans a hand for all those 'nyeh heh heh's he managed. Those take a lot of energy.**

 **I also wanted to mention that in my own playthrough I had always intended to finish all of Genocide mode but when I finally killed Sans and the reality of what I'd just done to him crashed over me I couldn't stop myself from hitting the ESC key and quitting as fast as I could. I was so worked up afterwards I had to take a shower and everything. Afterwards I RESET and then watched the rest of it online. Ironically, I'm really glad that I quit when I did because apparently Chara possesses you if you complete the mode and then it screws over any later pacifist endings? Yikes!**

 **Right now my game file is happily living on the surface and I intend to keep it that way hehe. :P**

 **Next chapter up on Thursday!**

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	14. Chapter 14- UNDERSWAP PT4

**Okay everyone, we're getting towards the end of this arc which means I'm looking for AU recommendations again! Literally anything is on the table so just send me a review or PM with what you'd like ^_^ (even PTA Sans bless his passive-aggressive heart)**

 **Current AUs on the table: HumanTale, OuterTale, Fusion AU, UnderLOID, HaremTale, Bromalgamate, GasterblasterAU and mooore**

 **[POLL IS OVER]**

 **.**

 **Big stuff happens at the end of this chapter oh boy! And you guys get to hear from someone you've been wanting to for a while now. -winks furiously- Enjoy!**

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WHATEVER CAN HAPPEN WILL

CHAPTER 14- UNDERSWAP PT.4 - SURPRISE GUEST

Frisk was standing alone in the middle of the throne room as Sans stepped cautiously through the shortcut. At least, he thought she was alone since he couldn't see anyone else in the room. That didn't mean Flowey, or whatever strange reversal of Flowey existed in this universe couldn't be lurking about. Frisk was facing away from him.

Unlike the dark, charred Throne Room of the last universe, this one was just as Sans remembered. Pure, white sunlight filtered through clean crystals to bathe the golden flowers in its nurturing rays but the big-boned skeleton couldn't help but check each one for any sign of a face.

"frisk? 'something wrong?" Sans asked as he approached the human cautiously. He could see a tension in her shoulders as she clenched and unclenched her hands without turning around. More of those little red flags popped up in his mind, warning him to keep away.

Sans stopped about three meters away, knowing better than to ignore his instincts as far as Frisk was concerned.

"frisk." Sans said, pitched lower this time. He didn't mean to say it like a threat, but it sounded like one in the suddenly oppressive atmosphere. The smell of flowers was overwhelming. "we don't have time for this. the other monsters are coming here right now 'n you said flowey was..."

His voice trailed off as Frisk's head turned slowly, followed by the rest of her. She was moving woodenly as she stepped with one leg first, then the other.

"H-help me..." Frisk whimpered as Sans' eyesockets widened. Thin vines had coiled themselves around every part of her including her face and their wicked thorns were drawing blood in a dozen places, wherever she tried to resist. "I-I couldn't - agh!"

Sans jolted as Frisk screamed suddenly, the vines around her throat tightening and cutting into the delicate skin there.

"Shut up, won't you?" A nauseatingly familiar voice spoke from right behind Sans. He tried to teleport away but the vines were on him before he knew it, leeching his magical power the more he struggled in their unbreakable grip. "I should really _kill_ you for being such nuisances, snooping around in my timeline and trying to get between me and my _fun_. Idiots."

Flowey's main bloom drifted before Sans' face, sneering down at him. He gasped as a vines snaking through his' ribs and spine tightened painfully, threatening to break him in half.

"And what's worse, you stole my other human souls! With the one soul I've already got locked up in here," Flowey motioned to the center of their main stem, which did indeed seem to glow with a hungry red, "I could've broken the barrier and let everyone out. Don't you _want_ that?"

Sans wanted to spit in the damn flower's grimacing face but he couldn't afford to indulge himself like that without access to his magic. He had to think.

"you're- ack- being tricked." Sans barely managed more than a whisper against the sharp pain. Flowey was looking him over carefully now, confusion playing over its shifting features and simplifying them into two dots and a line.

"You think I don't know about _Gaster_? Don't think for a moment I don't know you're in league with that... _thing_. I should snap you in half right here... but that would be a _waste_ of such novel toys." Flowey crooned, reaching out to brush a wide leaf across Sans' forehead tenderly. It was gaining confidence again. Sans' death-stare in response only made Flowey snicker. But wait. Was this Flowey? The weed Sans knew certainly acted in the same sociopathic way but it had never had those circular patches of pink blush coiled around the edges of its mouth. Its eyes had never glowed red with bloodlust.

 _oh. shit._

"Chara?" Sans asked hoarsely.

Flowey froze.

That had been a dumb thing to say.

" _How_ _do you know that name!?"_ Chara-Flowey screeched and with an excruciating jerk pulled Sans off his feet and let his entire weight hang on those magic-siphoning thorns. "Why are you here? Why did Gaster send you?!"

Sans tried to answer but the pain was too much and the rapid loss of magic was making his vision swim. Sensing this, the murderous plant losened its grip slightly but dashed him against the ground for good measure, cackling gleefully as it did.

"Sans!" Frisk cried from where she was still immobilized.

"Oh?" Chara-Flowey purred and Sans felt himself being lifted up again. The feeling of being trapped by these hateful vines was surprisingly familiar to him. "Does the human actually _care_ about this fat, stupid excuse for a sentry? Or..."

The weed turned them both so they were facing eachother, just a little off the ground like they were a pair of Papyrus' action figures. Sans blinked, trying to clear his head from the impact he'd just taken but he was losing power too quickly.

Still struggling against the vines, Sans had to admire Frisk's determination despite the futility of their situation.

 _just give up. i did._

Those words echoes in Sans' skull, giving voice to his innermost despair. Really, what point was there in struggling anymore? His Papyrus was long gone and they'd never be able to stop Gaster in the long run. Eventually he or Frisk would make a mistake or simply meet a challenge they could not overmount. Why even try?

Chara-Flowey had "walked" the two of them face-to-face such that Sans would only have to crane his head forward to touch Frisk's nose. A maze of tiny vines covered the peripheries of Frisk's face, drawing little red lines down her cheeks and over the now-purple bruise Sans had given her.

"Could it be more than just caring? Could it be _love_? Or is it LOVE? I always get those two confused," Chara-Flowey cackled again. "Either way, you two should kiss! C'mon Sans, kiss the human! Show Frisk how much you LOVE her."

Sans was aware of the fact that Flowey had just referred to Frisk by her actual name, but now he was being mashed up against her and there wasn't much room for thought. Chara-Flowey was actually trying to get them to kiss by simply holding them together and commanding it? _what a child._

 _-CRACK-_

A loud bang from the entrance doors brought them a moment of merciful distraction. Then, with a deep grinding noise the stone double-doors swung inwards and Asriel Dreemur strode in timidly. Chara-Flowey had gone perfectly still though their vines maintained their crushing pressure.

"Oh?" Asriel squeaked when he noticed the bizarre tableau before him but the doors had already swung closed behind him with an echoing finality.

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It was dark. That was the first thing Papyrus noticed when he opened his eyesockets. Or, at least he thought they were open? There really wasn't any difference. Feeling around the edges of his orbital cavities with his gloved hands he decided that yes, it really was just that **dark**.

Papyrus became aware of the fact that he was floating in the darkness and had no idea which way was up or down. Was he underwater somehow? How he somehow ended up in the ocean and just sunk down to the very bottom, alone?

"SANS?" He cried into the blackness.

But nobody came.

Fumbling in the darkness for his cellphone in his hip-pocket Papyrus was surprised to instead find Alphys' timeline-switcher-device. Or at least, that mean Alphys who'd kept him in a cage while she watched his brother fight... another Sans... on TV? None of this made any sense.

Disjointed memories of that ordeal drifted around his skull, still a little hazy from when he'd gotten knocked out by impostor-Sans. He remembered reaching out with his magic for the remote on the floor, his arm stretched towards it through the narrow bars of the cage up to the shoulder joint. Alphys had been screaming at something on the computer screen and then had began wailing as a bright flash of light caused the camera in the Throne Room to disconnect.

Papyrus had dropped the timeline-switcher remote in fear halfway to his cage when she'd turned back towards him.

Then she'd started laughing. Then sobbing. Once she'd started bawling in a little yellow heap on the floor Papyrus had forgotten his fear and only wanted to comfort the poor yellow dinosaur-monster. He'd learned his lesson about assuming there was good in everyone but there he'd been, presented with the proof of goodness still clinging to Alphys' soul in her grief.

Forgiveness had always come naturally to Papyrus.

He'd called out to her then, making her crested head snap up in alarm. She still looked scary, but Papyrus could tell something was different now. He told her everything was going to be alright.

She told him it wouldn't.

In the present, wrapped in his cocoon of darkness Papyrus couldn't help but agree that he'd gone from the spaghetti-pot into the oven... well, a really, really dark oven. There were noises in the dark with him, Papyrus realized: Humming like voices whispering over each other until nobody made any sense like that one field of Echo Flowers in Waterfall. He wished his big brother were here.

Papyrus remembered asking that other Alphys for help escaping her own jail and had pointed to the time-switcher by her feet. She'd told him that the device was unfinished but then a huge chunk of ceiling had shaken itself loose and crashed into the ground right beside his cage, making them both shout. He'd said they needed to leave together and she'd nodded. He'd believed her.

However, when the time came to press the button on the device, Alphys had suddenly let go. There was nothing Papyrus could do. He watched as if from the end of a long, receding tunnel as the room he'd just been in collapsed with Alphys still in it! At least in his final glimpse of her she'd seemed happy despite her streaming tears, standing straight and unhunched, fists at her sides, looking up.

Then blackness.

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Not a moment after Asriel entered the Throne Room entrance, the King- no, Queen! entered through the rear door. Toriel looked magnificent in her trailing cloak and heavy plate-armour but her expression was so sad and defeated, it made Sans ache for her. Maybe Chara-Flowey would give them a moment to catch up and share some bad puns?

 _probably not._

"Aw, looks like our playtime is over." Chara-Flowey whined, angling their petals downwards as if in disappointment. The vines didn't relax one iota.

"W-what is the meaning of this?" Toriel bristled and took a step back as she saw them. But her doors had closed behind her too, there would be no escape. Then her ruby eyes noticed Asriel cowering over by the main doors and the hint of a smile warred against the fear that had frozen her lips. She called out to her son with a name that was _not_ Asriel and belatedly Sans realized that the original Asriel was probably long-dead, like in the Alpha timeline.

Not-Asriel bleated for him mom and the two of them ran for each other , trying to skirt the snarl of vines that chocked the once-pristine garden. Chara-Flowey waited until they were within arm's reach before stopping them, the sick _weed_.

"Not so fast!" It taunted, holding little not-Asriel upside-down by a leg. They thrashed against the vine and called for Toriel but it only made the murderous grin on Chara-Flowey'd face grow wider. With a sick feeling where his stomach would have been, Sans recognized that smile. He looked to Frisk, who had gone back to struggling against the vines again but seemed transfixed by the smile as well.

Flowey-Chara brought the little boss-monster to within arm's reach of their flat, horrifically smiling face and the child stopped struggling immediately, instead shrinking into himself and quivering.

"I need you to tell me where the souls are." Chara-Flowey purred as its eyes shifted over Sans and Frisk, its vines tightened painfully. "You're a different Sans from the one I've played with, but I don't think you'd just stand by and let me kill this one." The vine holding not-Asriel wiggled him back and forth.

"You will not hurt my chi-!" Toriel had started shouting but Chara-Flowey simply hefted the Queen and tossed her full-force into the entrance-doors. This was accompanied by a flash of red from Chara-Flowey's core, which did not escape Sans' notice. Now that the plant's attention was elsewhere, he could feel his magic slowly returning. Sans winced as Toriel hit the stone doors so hard they cracked along the horizontal axis and buckled outward slightly. The Queen flopped to the ground, unconcious but mercifully alive.

"Shut up, Mom." Chara-Flowey sneered and gave a hollow attempt at a giggle.

"We aren't working with Gaster!" Frisk shouted, speaking up for the first time.

"Oh?" Flowey turned to look at her instead. "And what if I don't _believe_ you? Is it just coincidence that the two of you show up here the _instant_ that creep waltzes in here and grabs the souls right out from under me?"

Sans was a little taken-aback at Chara-Flowey's phrasing. As far as he was aware, Gaster didn't 'waltz' anywhere. Lurk, maybe. Creep, definitely... but 'waltz'?

"heh. sorry to _tango_ up your plans, but we're still not workin' with Gaster. We're just tryin' ta get home ourselves." Sans grinned, feeling his magic returning a little bit more and with it his habitual smugness. Chara-Flowey shot him a disbelieveing glare. "what, did i _mambo_? _**let. us. go**_."

Luckily, the main doors took that moment to finally crumble outwards revealing an entire crowd of monsters just beyond the threshold. The assembled cast seemed frozen by the sight of their Queen laying unconscious at their feet and by the huge plant-monster that had engulfed the majority of the room with its thorny vines. Unsurprisingly, alternate Sans was the first to act.

"everyone! protect the prince!" Alternate Sans shouted at the top of his lungs and charged. There was a slight pause between his battle cry and when the entire crowd surged into the room, circling around Chara-Flowey's massive form and drawing their magical weapons. Alphys had mobilized the entirity of the Royal Guard and their menacing presence gave the mob some credibility as an actual threat. Sans felt himself get lifted into the air away from them as Chara-Flowey attempted to preserve her hostages.

"let 'em go!" Alternate Sans cried again once Chara-Flowey was completely ringed in. The plant actually looked concerned at this development. Sans locked eyes with his heroically-posed doppelganger and was for once completely devoid of embarrassment for his dopey double. This armour-clad Sans was serious, but still managed to exude hope so powerfully it made even Sans begin to believe they had a chance.

"I-I... I..." Chara-Flowey was stumbling over their words, the pink rosettes of color on their cheeks becoming more pronounced.

Then their expression snapped back to hideous glee.

"YOU-"

But before they could tell everyone just how big a pile of idiots they were, a sharp snapping noise resonated through the room. Sans' breath caught and his magic reacted on instinct, burning bright blue. But he was frozen.

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.{Y.O.U. .I.D.I.O.T.S.}.

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The sharp, even rapping of footsteps cut the absolute silence as a figure emerged from the rear entrance. He was tall and thin and moved with an easy grace through the trampled flowerbeds. A black, fitted waistcoat and slacks ended at well-polished dress shoes which remained unscuffed despite the churned-up mud he was walking through.

Clack, clack, clack went the heels of his shoes against nothing hard enough to make that sound.

The man-shaped monster straightened the cuff of his undershirt with a long boney hand with a hole punched through the palm.

As if flowing in a non-existent breeze, the long, black cloak he was wearing flapped lazily behind him as he strolled past the outermost monsters, all of which seemed to cringe away despite begin frozen in place. The cloak was actually a lab coat, Sans realized, but his father hadn't bothered to put his arms through the sleeves and had left them bunched around his shoulders.

Alternate Papyrus and Sans' eyesockets had gone so wide Sans thought they might crack.

Finally, W. D. Gaster stopped before Chara-Flowey's main stem and looked up at them with that cracked mask of his. It still had those cracks above the right eyesocket and below the left one, but now it was also bifurcated into right and left down the center.

Gaster smiled.

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 **Oooooooh boy! Here we go! Heeeee's back, in the flesh! -scurries off to make some fanart for my own series lol-  
**

 **Also someone asked me if I have a tumblr and yes i do, it's 'Spooopyskeletons' with 3 'o's. I don't post too much but I did recently make a picture for my boyfriend which I posted on there of the two of us playing undertale. It involves Sans in a dress so you guys should check it out: spooopyskeletons. tumblr (.com) / image/ 134840712934**

 **Yes UnderSwap Sans pulled a 'Llleeeeeeeeeroooooyyyy Jeeeeeenkinsssss'**


	15. Chapter 15- UNDERSWAP PT5

**So here we are at the end of the Underswap arc! It's so much fun writing void-Gaster I'm almost tempted to write a sister-fic about him but I don't want him to lose any of his mysteriousness. His fighting style is also really cool in my imagination, like Sans' time-skipping but with a physicality to it that is up-close and personal. He's got some serious reach, after all.  
**

 **Art of Gaster is up on my tumblr here: spooopyskeletons .tumblr. (com/) image/ 135102897274**

 **Well, chances are we'll see him again pretty soon since as of now BromalgamateAU is in first place in the polls with UnderLOID in second! Details about what each AU entails can be found in the poll itself.  
**

 **[POLL OVER]  
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 **I also just wanted to say that all of your reviews give me life and more joy than I can describe whenever I get one :)**

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WHATEVER CAN HAPPEN WILL

CHAPTER 15- UNDERSWAP PT.5 - YOU WILL NOT TAKE THEM

"DAD?" The alternate Papyrus peeped. The quiet syllable hung in the silence of the Throne Room, made all the louder by the fact that none of the hundred-odd monsters crowded onto the ruined gardens were breathing. The fact that Papyrus had managed to speak at all was startling to Sans, considering he was completely immobilized by Gaster's magic. Unless he was just paralyzed by fear?

W. D. Gaster tilted his head at the little noise as if trying to remember what it meant. His black labcoat-cloak rustled slightly in its private breeze, exposing the underside which glowed in a neon spectrum of orange-through-violet. Chara-Flowey began coiling and uncoiling its vines again, emboldened by the interruption.

The dark-robed skeleton's jaw worked beneath his cracked mask but the hard plane of his face remained unchanged, like a lily pad over rippling water. Or an oil slick, in this case. Even from his high vantage point where Sans was being held by Murderweed he could see that the _shape_ of his father's body resembled what it had been in life, but the matter comprising it had changed. What had once been white bone was now ridges and protrusions of black ooze only mimicking a skeleton. The top of Gaster's black skull was dripping as if he were sweating, only the drips were falling _up_ , only to evaporate an instant later.

"DAD, IS THAT YOU?" Papyrus found the courage to speak again somehow, his hands leaving the pockets of his hoodie and reaching out palms-up. The black matter of Gaster's body rippled again.

.{N.O.}.

Papyrus's face fell, all hope draining away. Beside him, Alternate Sans made a little choking noise.

Another ripple.

.{A.N.D. .Y.E.S.}.

Gaster spoke strangely in this form: His mask didn't move from its frozen half-smile nor did he emit any noise. The words simply found their way to you, without needing superfluous things like soundwaves. The sound of it hurt Sans' head yet soothed him paradoxically. The echo of his Dad's voice was in there, and it made his soul ache.

"So you _are_ in league with the skeletons." Chara-Flowey's voice seemed a bit shakey, but that could've been Sans' imagination. Their vines tightened painfully on his middle again, grinding his ribs together.

"augh!" Sans cried out at the invasive feeling of thorns cutting at the inner surfaces of his ribs. Frisk yelped as well and Sans felt his magic leap protectively, only to be quickly siphoned off by the hungry brambles. _stupid!_

Gaster's head snapped up to look at him. In concern? Annoyance? Fear? The mask was unreadable.

"He's - ugh!- not here for us, Chara. He's here for _your_ soul!" Frisk shouted as she continued struggling. Her bright-blue eye flashed a warning in the refracted sunlight.

" _My_ soul?" Chara-Flowey giggled, quickly regaining confidence. "I haven't had a soul in a thousand years!" The joyfully murderous smile Chara had always worn when anticipating a kill split the flower-monster's face. It moved Sans, Frisk and not-Asriel away from it's main stem which was still glowing that same dull red that Sans knew and loathed.

The space where the glow was strongest opened up as if it were a vertical, toothless grin in Chara-Flowey's stem. Inside was...

Sans heard Frisk's sharp intake of breath.

Whimpering and crying in jagged fits, the small child inside Chara-Flowey's "neck" was undoubtedly Frisk. Same unkempt haircut, same ratty, over-sized blue-and-pink sweater. Same crimson soul beating frantically.

Here was Frisk as Sans had first seen her, all those timelines ago. So many repressed memories flung themselves to the front of his mind of her and of trying to protect the other children who'd fallen into the Underground. And how he'd failed all of them. The groan that escaped him this time wasn't caused by physical pain.

"Nobody even noticed when this human fell into the Underground. Lucky me I grabbed her before the King could find her, hehehe!" Chara-Flowey's saccharine voice grated.

Young Frisk's limbs were splayed like a four-pointed star and her hands and feet were completely hidden in a mess of pulsing, reddish plant matter. It was siphoning off their power and determination just as it was with Sans and Frisk!

.{.G.I.V.E. .I.T. .T.O. .M.E.}.

The command in that razor-sharp not-voice made Sans shiver, and he felt Chara-Flowey tense as well. Gaster raised a punched-out, surprisingly solid-white hand as if in supplication, but the bright violet magic that swarmed around his long fingers was not asking.

A moment of silence-

"Hehehehe! How about. _NO._ " Flowey screeched and the window in its stem slammed shut on the Frisk imprisoned there. "How about instead... you give me _YOUR SOULS!"_

-and the world went white.

.

.

Papyrus almost discarded the distant glow as his imagination. He'd been floating in the solid darkness for goodness-knows how long and frankly he was getting pretty loopy. At first he'd tried making big, swimming motions but that had gotten him nowhere. He still wasn't even sure if he was underwater or not. It didn't _feel_ like he was, but the pitch-darkness around him was so thick it almost felt like liquid.

Next, after stowing the Timeline-Switcher safely in his pocket he felt around for his old sharpie and pulled it out. The last time he'd held it had been right before his greyed-out brother had died in his arms and just feeling it made Papyrus' bones rattle... But Sans _wasn't_ dead. He'd seen him! Well, on TV at least, but that Alphys had acted like it was real, so Papyrus decided to believe her.

Briefly letting go of the Sharpie but keeping it cupped in a dome of his boney fingers, Papyrus tried to figure out if there was any movement or flow to whatever he was hanging suspended in. He couldn't see it, but he could tell that the marker wasn't being pushed into any of his fingers at all. It was just sort of... suspended. Like he was. Weird.

He tried about a dozen increasingly half-baked plans at escaping or figuring more out about his prison but eventually even the Great Papyrus had been stumped.

He pulled out the timeline-changer again and considered the big, heart-shaped button in the middle of it. He put the tip of one finger on it and tried to gather up the courage to press it, but he couldn't help but feel that every time he'd used the remote things had only gotten worse. He put it away, resolving to use it only if there was no other choice.

Finally, Papyrus pulled out the little glass vial that Alphys had given him, the one containing bits of Sans and the human's souls. It actually glowed a little in the smothering darkness, but not nearly enough to illuminate his surroundings even if there had been anything to illuminate. Instead, Papyrus was just content with basking in the glow of his brother's soul, tiny though it was.

He'd been so fixated on it he almost didn't notice when the distant glow turned into a distant glimmer of white. Papyrus blinked, putting the vial back in his pocket where it would be safe and focusing on the pinprick of white that seemed like a lone star in a sea of black. It reminded him of Sans' pupils. The light twinkled and grew brighter, making Papyrus' soul leap in excitement.

Whatever was happening, it'd be better than just sitting here! He hoped.

It felt like the white light was getting closer and closer, or maybe Papyrus was just getting closer to it? He reached out to it.

.

.

Sans shouted as the blazing white light burned past his hands and closed eyesockets and blinded whatever passed for his retinas. An agonizingly sharp pain bit into the space below his sternum and sent tingles through his limbs like an electric shock.

"eeeeaaaaaaaagh!" Sans screamed, his fingers scrabbling at the ridges of his eyesockets vainly against the overpowering light. He couldn't see it, but he could feel his soul straining against him, being dragged out of him!

 _this is it. i'm gonna die. papyrus, please don't be mad at me._

But then Sans felt hands grabbing his wrists and pulling them away from his eyes. Soft, familiar hands that held him tenderly but firmly and quickly drew him into a hug. The white was blinding, but Sans could feel the way those hands snuck between his unzipped hoodie and the t-shirt below and couldn't quite reach all the way around him.

"I'm here, Sans." Frisk said, her face muffled into his front as she hugged him as tightly as she could. Slowly the pain receded and Sans could feel Chara's grip on his soul weakening until it was only a slight tug, like fingers on his ribs.

The light dimmed and died, leaving huge, black-blue spots in Sans' vision. Around them, he thought he could see the Throne Room but the crowds of monsters were gone. Frisk yelped as the room tilted and something hit him hard on the side of the face.

Oh. He'd fallen over.

"S-Sans! get up!" Frisk pleaded at him, pulling at his hoodie.

Three different puns about napping sprung to mind but he was too tired to make any of them.

"Sans! It's Papyrus!"

Sans' eyesockets snapped open in an instant, followed quickly by the blue fire. After spending so many years going numb inside, the emotional roller-coaster of the past few days made him feel like he was fraying at the edges. Around them, uprooted flowers littered the ground in yellow heaps, though the thick vines that had pulled them up were gone now. The throne was in splinters off to one side and two figures now faced off in the middle of the room.

The dark, now-hunched-over form of Gaster and the small, menacing child that could only be Chara.

Sans didn't care about either of them though because right behind Gaster was a pile of skeletons that included the orange-hoodied alternate Papyrus, the armored alternate Sans and... and...

"papyrus!" Sans cried and struggled to his feet with Frisk's help. He took a step towards his brother, stumbled and got back up again.

Extracting itself from the jumble of bones, a familiar face noticed Sans and lit up like Christmas.

"S-SANS?" Papyrus, _his Papyrus_ with his orange scarf and polished battle-body found his feet as well and ran towards him, closing the distance in three bounds.

"i-i'm so s-sorry, paps. i-i..." Sans couldn't believe this was real. He must be dead and the afterlife was paradise after all. Round, blue tears streamed from his eyesockets as his tall little brother scooped him off his feet and pulled him in tight. "i couldn'... i-"

"SSSSHH, BROTHER. IT'S ALRIGHT. I AM HERE." Papyrus murmured a stream of reassuring noises and pressed his teeth to Sans' forehead, tingling the bone there with a magical kiss. "I AM HERE."

Sans hadn't realized just how much emotion he'd been pushing down since getting his soul fused with Frisk's. The ferocity of his relief at holding _his_ Papyrus again was overwhelming and soon the two of them were just crying in each other's arms. Distantly, Sans was aware that Frisk had positioned herself between the two of them and the two powerful monsters squaring off not three meters away.

.{Y.O.U. .W.I.L.L. .N.O.T. .T.A.K.E. .T.H.E.M. .F.R.O.M. .M.E.}.

Papyrus wiped some of the tears off Sans' cheekbones lovingly and angled himself between his older brother and the potential threat. This was wrong, Sans thought. He should be the one protecting Papyrus. However, the way his lanky brother's arms surrounded him was too comforting to pass up.

"Oh?" Chara chirped, stifling a very Flowey-esque giggle. "That was a stupid thing to do. It must have taken a lot of energy to keep their souls from me."

Sure enough, when Sans took a closer look at Gaster, he really wasn't looking too good. Whereas a moment ago he'd stood straight and regal, now he was hunched over and dripping black ooze onto the dirt. The technicolor lab coat had also lost some of its distinctness and was merging with his amorphous shoulders.

"I'll take the souls you stole now. And then I can finally be _free_!" Chara grinned hideously. She had found a knife somewhere and was holding it confidently in front of her now, the tip aimed at Gaster's mask.

Still, Gaster looked over his shoulder to look at both sets of Sans an Papyrus, as if checking that they were okay.

.{Y.O.U. .W.I.- .Y.O.U.- .Y-}.

Violent ripples shuddered through the void-monster's body and his bone-white fingers convulsed. Chara took a step forward but paused.

.{.H.A.H.A.H.A.H.A.}.

Gaster's head snapped up towards Chara then, and his fingers stilled abruptly. The garbled-dialtone laughter made Sans' magic leap in remembered fear and he felt his hands tighten around Papyrus protectively.

Like clay on a potter's wheel Gaster's body condensed into the shape it'd had before. His hunchback straightened and his limbs regained their definition.

.{A.H.A.H.A.H.A.}.

It was as if two monsters inhabited the same body. One of them was Sans' father, but the other... That maddened cackle was like nothing he'd ever heard before. W.D. Gaster reached out then with his violet magic and pulled Chara into the air, making her stolen soul manifest over her chest as she prepared to fight.

"wait! dad, what're you doing?!" Alternate Sans dove between Gaster and Chara then, striking a heroic pose despite his obvious fear.

"SANS!" Alternate Papyrus cried, moving forwards to pull his brother away to safety.

"dad, are you in there? why are you doing this?" Alternate Sans would not be moved no matter how his taller brother pulled at him.

"get back, kiddo. that's not our dad anymore." The alpha-timeline Sans stated. His Papyrus was looking intently at the scene before them but said nothing.

"you're wrong!" The blue-scarved Sans shouted angrily at him, trying to shrug out of his brother's grip. The blue star-like points of his enthusiastic eyes had become bright and serious. He turned back to Gaster. "i know you're in there, dad! you wouldn't kill a human, even if it meant you could break the barrier!"

Sans cringed at just how wrong this naive Sans was.

.{O.H.?}.

The void-monster straightened imperceptibly and no ripples marred the sleek surface of his body this time. If there had ever been a monster with fewer qualms about sacrificing human lives for the good of monsterkind it had been Sans' dad.

Sans felt the memories click back into place in his skull. Shrill screaming and flashes of blue. Out-of-control magic. Time reaching down and _shredding_.

"God, you're such an _idiot_." Chara said from behind the alternate Sans, and lunged with her knife.

.

But never connected. Chara's red eyes widened when she realized her wrist was being held between Gaster's vise-like fingers. A ravenous humming filled the room. Then, with a sound like a whip cracking time stuttered and suddenly Gaster had thrown the small child through the air, but she'd already collided with the wall.

-time hitched and there was child-sized dent in the ground

-another movement and one of the ceiling's crystals was smeared with human blood

-a severed arm

-violet light and screaming

Sans tried in vain to follow the action that seemed to happen all at once and not at all. Gaster was less than a blur. Whenever he moved it was as if he had already been there all along and the only evidence of something changing was some new wound Chara had sustained and a new splotch of red on the ground or walls or ceiling.

Suddenly Gaster was standing back where he'd started, holding Chara by the throat off the ground in a swarming cloud of violet. At first Sans thought she'd been killed, but the dull, slowly thumping soul over her chest was still whole.

Gaster's mask seemed to smile.

"no!" The alternate Sans cried, his eyesockets as wide as they would go. Alternate Papyrus was tugging him away, but this Sans was surprisingly strong. Gaster's head snapped up at the sound of a Blaster charging and Sans felt his own magic tingle at the familiar crackle of hateful magic.

With a burst of white and a piercing howl the GasterBlaster which had appeared above the alternate Sans discharged, aimed right for the hand Gaster was using to hold Chara.

Gaster recoiled, but the beam connected.

Both Gaster's hand and the alternate Frisk's soul were incinerated in the unplanned attack and the sad, echoing sound of the soul splintering filled the suddenly silent room.

Alternate Sans dropped to his knees as his brother ran forwards to protect him, but there was no need. Gaster was looking down at the small corpse at his feet, motionless. Sans felt his Papyrus begin shaking and it was all Sans could do to hold him closer and rub his back. Beside them his Frisk gasped and clamped her hands over her mouth in horror.

"i- i didn't..." Alternate Sans seemed confused as to what had just happened and was looking at his hands.

Gaster convulsed.

It started as a low keening that seemed to come from everywhere but quickly increased in volume until is was a savage screaming. Gaster took a tottering step back from the corpse, his remaining hand clasping and unclasping as if it had a mind of its own. Black ooze dripped upwards from him as the wailing continued.

.{E.E.A.A.A.A.A.H.!.!.!.}.

Gaster's lean body coiled in on itself as if in agony. And kept coiling and coiling until suddenly- he was gone. Only empty air and a ringing in Sans' hearing remained.

Alternate Sans fell to his knees with his brother still at his side. Then the only noise was a quiet sobbing.

The multitude of little white monster souls that Chara had kept inside her unfolded slowly into the air like a deck of playing cards. They lingered briefly as if in sorrow before whisking off into the Underground, probably to wherever they felt safest before re-manifesting their bodies.

"i didn't mean to- oh no nonono." Alternate Sans was moaning and still looking at his hands as his older brother tried to comfort him in a strange mirror-image of Alpha Sans and Papyrus' position. Sans looked up to see his little brother crying openly with a hurt and confused expression darkening his eyesockets. Slowly, Sans got to his feet but kept Papyrus' hand firmly clutched in his own. Frisk hovered beside them, giving Sans a searching look that seemed to ask for a hug of her own. Papyrus, bless his soul, beat him to it by pulling the human under his other arm as they walked as a group over to where their alternate selves were grieving.

"HEY. UM, SANS?" Alpha-Papyrus knelt in front of the alternate brothers, bringing Sans and Frisk down with him to the warm dirt. The other Sans' tear-soaked face tilted up slightly, but his pupils still seemed glued to his shaking hands. "IT'S GOING TO BE OKAY. YOU DIDN'T MEAN IT."

Alternate Papyrus was looking at Alpha Papyrus with a strange expression that made Sans' hackles raise protectively. It was a questioning look, as if searching for any sign of a threat. After everything that had just happened, Sans knew he would be feeling overprotective in his shoes, but still he couldn't keep his augmented magic from brightening his eyes

"but how'd i do that?" Alternate Sans was oblivious to his older brother's concerns. "i've never used magic like that before."

"IT WAS JUST A FLUKE, BRO. YOU WERE SCARED." Alternate Papyrus whispered, his attention returning to his brother.

"it felt... _awful_. my bones feel greasy from it, like i spent too long in grillby's."

A brief chuckle escaped Alpha-Papyrus at that, but he quickly clamped down on it. The two older brothers looked abashed and Frisk just grinned a little. Alternate Sans noticed the exchange and his expression softened as well.

"i mean, it was pretty _slick_ , but i don't think _oil_ be doing it again." Alternate Sans continued, his grin widening a little.

Both Papyrus' stiffened.

"i gotta a _grease_ with you there, sans." Alpha Sans took the hint. "you're looking pretty _fried_ , but at least it's over now."

"OH MY GOD, SANS!" Both Papyrus' moaned in tandem, breaking the tension and letting Frisk unleash the giggles she'd been stifling. Then she snorted and the rest of them followed suit in slightly-hysterical laughter.

The light filtering through the crystals had begun to dim as daylight on the surface waned, but Sans' spirits were brighter than they'd been in recent memory. His Papyrus was back and was groaning at his puns which meant everything was right with the world. At least for now. The overactive part of his mind told him that Gaster was still out there and wouldn't stop until he got Frisk's soul... but that could wait.

"Sorry we couldn't help you guys break your barrier." Frisk said, addressing the alternate brothers.

Alternate Papyrus simply shook his head, grinning and lighting up a 'cig. Alpha Papyrus and Alternate Sans both crinkled their nasal bones in distaste of the pungent smoke but neither cared enough to ask him not to.

"S'FINE. THINGS WOULDA BEEN A LOT WORSE WITHOUT YOU GUYS, I THINK." Alternate Papyrus conceded.

"ahem. if you don't mind me asking... who are you guys?" The sincere confusion that lit alternate Sans' face made Sans grin all the wider.

"THAT'S PROBABLY A LOT MORE COMPLICATED. THAN YOU THINK IT IS?" Alpha-Papyrus responded before Sans could decide what to say. He didn't want to overstep his bounds, considering that these brothers would probably have to have a pretty serious conversation about what had happened. And what hadn't been shared between them beforehand. Sans considered that he'd have to have the same talk with his Papyrus.

"YEAH, PRO'BLY. HEH. WE'LL BE FINE, THOUGH. MORE HUMANS WILL FALL DOWN HERE EVENTUALLY. YOU GUYS SHOULD GET GOIN'." Alternate Papyrus dismissed them gently, but Sans didn't need to be told twice. He nodded at his reversed self and stood, taking Papyrus and Frisk with him.

"yeah. prob'ly should." Sans confirmed.

"BUT WHERE. WILL WE GO?" Papyrus asked, not seeming overly concerned.

"Home, hopefully," Frisk replied with a faint smile. "But chances are it won't be that easy."

"GOOD. I LOVE AN ADVENTURE." Papyrus smiled.

The trio bid the alternate brothers farewell one last time and Sans guided them to a promising-looking shortcut. He'd have to explain everything to his Papyrus now, but oddly the prospect of that wasn't as scary as it'd once been. They stepped into the fold in space-time together and experienced a moment of weightlessness, a slight squeezing and-

.

.

* * *

 **There we have it! UnderSwap arc: complete!  
**

 **I'll be writing another bridge chapter between this arc and the next, like I did last time. That way everyone has a chance to vote in the poll who wants to. :)**

 **[POLL OVER]**

 **Also it's fun to have some of you guys as followers on my tumblr which is again 'spooopyskeletons' I'm still working on a big dump of arts so stay tuned for that! Thanks everyone for your continued support. Next chapter will be up TUESDAY (Dec 15th).**

 **P.S. Something is funky with my pageview counter. It's been stuck at the same number for days and doesn't seem to getting new data on views at all. I'm still getting notified about favorites and followers however. Does anyone know what might be causing this?**


	16. Chapter 16- MEMORIES PT2

***It's a little-known fact that monsters invented basketball and humans just stole the idea ;)**

 **Also, it is unclear as to exactly how long a monster takes to fully mature. It may even be different for each one, considering that in the actual Undertale game Papyrus acts similarly to a young teenager. That may have something to do with Sans' coddling him, though. In this fic, I'm going to leave the exact timeframes for the monster's maturation open-ended but I'm assuming Chara falls into the Underground a decade or two after the War.**

.

.

* * *

WHATEVER CAN HAPPEN WILL

CHAPTER 16- MEMORIES PT.2 - LOVE

As with before, Sans felt time stretch around him as he slipped into the space between universes. What was this space called again? The _bulk?_ There'd been a time when things like that had fascinated him and made him dream of the stars he didn't think he'd ever see again. Now, he just wanted to go home with his brother and Frisk. He didn't care about breaking the barrier particularly. He just wanted to go home.

{{{{{Monsterkind hadn't been so elated since before the War. It was all anyone would ever talk about: The human child who'd fallen down and been adopted by the young King Asgore and his queen Toriel. Apparently the kid was of an age with the Crown Prince and they were close as bunnies in a bed.

"Are these the data extrapolations?" Gaster asked as he took the proffered clipboard from Sans. His long forefinger trailed along the sprawling calculations with enviable ease as Sans' brilliant father processed the new information.

"yeah, but they're not a hundred percent yet. still don't have enough information on human souls, 'n queen toriel won't let us test her kid." Sans grinned to cover his blush, remembering his embarrassment after the queen verbally tore him a new one when he'd asked to test the human on his dad's behalf.

"Still. This seems promising." Gaster stroked his boney chin. "We're getting close to powering the CORE, I can feel it."

Sans' grin became more natural as his father praised his work. Along with everyone else, Sans felt more hopeful than he had in a long, long time. Maybe soon, once the CORE was built and monsterkind had a stable source of energy to grow food he could begin work on his real passion: Quantum mechanics, especially pertaining to time travel.

Returning late as usual to their two-level house in New Home, Sans was practically knocked off his feet by the force of Papyrus' 'Welcome Home!' hug.

"hey bro, what's up?" he asked, his face being crammed into Papyrus' sternum.

"YOU KNOW WHAT 'SUP, BROTHER! I HAVEN'T SEEN YOU OR DAD. IN ABOUT A WEEK!" Papyrus shouted, making the windows rattle.

Sans blinked against his brother's T-shirt. Had it really been _that_ long since he'd been home? Wow.

With some haste, Papyrus helped Sans out of his white lab coat and tossed the grimy thing into a hamper across the room in an excellent 3-point shot. Being so tall, Papyrus had been drafted into the New Home basketball team and was actually really good at it. Sans loved cheering him on at games when he had the time to attend, which had been less and less often recently.

Papyrus' empty sockets looked Sans up and down appraisingly.

"YOU HAVEN'T BEEN EATING, SANS." The lanky skeleton crossed his arms.

Sans shrugged and started changing out of his work-clothes as he made for the living room. He fumbled a little with his clip-on tie and button-up shirt before collapsing bare-chested on the couch. Looking down at himself, Sans realized that he really was just bones. Not that that was anything to worry about as a literal skeleton, but Papyrus was used to him having a bit of a layer from his university days.

"been busy." Was Sans' succinct answer. It was true, but he still felt bad that he couldn't say too much about the classified projects he and his dad were working on. It wasn't his fault that Papyrus was a notorious gossip. But he was being rude, Sans realized. "what've you been up to?" He asked.

Papyrus beamed at the attention in a way that never failed to make Sans' spirits brighter. They sat together for the rest of the evening as Papyrus warmed up a practical feast of pre-made meals for Sans and chattered on about life with his friends and their teenaged antics. Honestly, sometimes Papyrus could be a little overbearing with his care and enthusiasm, but Sans found it endearing.

Before long, though, Sans found himself getting drowsy.

"SANS?" Papyrus asked, nudging him in the leg with a boney toe. Sans blinked to focus his vision. "I SAID I WON THE AWARD. FOR BEST MAGICAL DUELIST!" Papyrus' eyes literally sparkled with pride as he pulled a little gold medal from his pants pocket and held it up to the light. Two sashes of deep blue ribbon trailed from it, reading '#1 MG DUELST'.

"t-that's amazing, bro!" Sans crowed, putting his hand on Papyrus' shoulder and giving it a proud shake. "you were already the greatest, now s'just official. c'mon, i think you've earned a bedtime story."

Papyrus' smile grew about 5 sizes wider at Sans' heartfelt compliments but he was trying not to let his joy show by tilting his skull back and crossing his arms.

"NYEH HEH HEH! I THINK THAT WOULD BE. AN EXCELLENT REWARD!" Papyrus chattered and practically carried Sans upstairs to his room.

"hey, let's not get _carried away!_ " Sans smirked from under Papyrus' arm. The answering groan was almost as good as a medal.

Deep down inside, Sans couldn't help but feel a little jealous of his brother. Papyrus was an extremely talented monster whose delicate skill in magic was matched only by the depths of his devotion to his friends and loved ones. Some monsters saw him as naive, but Sans knew that it was just that Papyrus had decided to believe the best in everyone, even knowing he wouldn't always be right. That took a lot of courage.}}}}}

.

.

{{{{{The human child was dead.

All the joy and excitement of the previous year ended in a single night as cruel fate stole away not only the human's life, but Prince Asriel's as well. The young boss-monster had been beaten to death by humans.

The labs were silent as a tomb the day after the news broke and Sans found himself shambling aimlessly through the corridors like the undead. He certainly looked the part, he thought drearily. He'd given up on his work for the day, knowing he'd get nothing constructive done in this black mood. Hatred for humanity coiled around his soul like brambles, actually causing him physical pain.

How could they have been so foolish? How had they ever thought they could ever be free again with those fleshy _abominations_ strutting about on the Surface?

 _filthy killers, the lot of them._

Without realizing it, Sans found himself in the section of the labs where his father worked. He considered turning around, but there was a tingling feeling in the air that drew him forwards. It felt so... _alive_. The thick doors of W.D. Gaster's main laboratory hissed open ponderously, making Sans feel very small. Inside, the air was thick with a strange, metallic scent like iron. The lights were off.

Sans considered calling out for his dad, but then heard the whispers.

"S-she l-left me. I c-can't believe s-she'd..." It was a deep, familiar voice underneath the grating tone of pain.

 _king asgore?_ Sans could hardly recognize the huge, weeping monster that was slumped over beside one of the lab benches. His broad cloak was torn across the shoulders as if someone had ripped at it with claws. The angles of the slashes led Sans to believe they were self-inflicted. The iron stink was closer now.

"She doesn't understand. This is something we must do, for all monsterkind." Sans' father's thin voice carried in the thick air. He sounded sad, but determined. Sans leaned a little further out from behind the machine he was using as cover to get a better look at the dim scene.

Gaster had one skeletal hand on King Asgore's shoulder as the king wept openly, practically on the floor. There was something red on the lab bench behind them, but Sans couldn't make it out. It gave him a bad feeling.

"Sometimes the greatest sacrifices yield the greatest rewards. Your father understood this." Gaster continued, looking now at the red thing on the table. Sans had never seen his father look so serious before, but it was only natural that a father wouldn't show his sons his darker side. It reminded Sans of the way he was with Papyrus, always grinning. Always protecting. "King Thade surrendered against his better judgement so that we could live on, so _you_ could live on. In the end, the pain of that decision killed him. That does not make it wrong."

Asgore shook his big head, groaning.

"Toriel would never have allowed our research to continue. Her compassion would have kept monsterkind trapped forever."

"B-but she - hic - was-" Asgore whimpered, slumping further.

Sans didn't want to see any more of this. Seeing his king like this... Sans had always known the big monster was soft-hearted, but to see him so vulnerable felt like a blindfold being torn away. King Asgore would never actively do what needed to be done to break the barrier if the sight of one human corpse- Sans realized what the thing on the workbench was at last- could destroy him like this.

He let out a shakey breath and left the room silently.}}}}}

.

{{{{{When Gaster came to visit Sans in his office the next day it did not come as a surprise. Sans' father cast a long shadow over the room as he loomed in the doorway, lit from behind.

"You saw us yesterday in the Lab." Gaster said without preamble. That did surprise Sans a little, but he grinned wider so it wouldn't show.

"yeah." Sans responded, knowing the was no point in lying.

Gaster strode into the small room, seeming like a shadow himself in his black mourning cloak. The whole of the Underground was still grieving for the lost prince and to a lesser extent the human that would have been their ambassador. As Royal Scientist, it was Gaster's place to be seen as in mourning.

Some monsters had accused him for not doing enough to save the prince, confusing his 'Doctor' title for that of a physician. _the idiots_.

Sans offered his dad a seat in a spare, creaky chair which he accepted gratefully, practically collapsing into it with his long legs extended outwards. However, the seriousness in W.D. Gaster's dark eyesockets belied his casual pose.

"So you know the Queen has gone into exile. Now that Asgore has vowed to take the soul of any human that falls into the Underground and break the barrier by force if necessary." Gaster was playing with the pin of his identification badge. The young Gaster in the photograph was smiling brightly in his frame, totally at odds with the present Gaster's pained expression.

"humans don't deserve any better." Sans sneered, looking away when he felt his dad's concerned gaze fall on him.

"Maybe," Gaster said, "or maybe not. I've known good humans too, but they always stayed silent when the bad ones went to war. Humans are strange, conflicted creatures capable of incredible love... and also LOVE."

Sans' eyes met his father's. Gaster had never had much of a poker-face and now the pain tugging at the corners of his eyes was plain to see. It had been a long time since Sans had learned about the concept of 'Level Of Violence' and how you could quantify a being's capacity to hurt by considering their previous actions. Each time you killed, it would get a little bit easier. It made sense, he supposed.

"whatever the price to my LOVE, i wanna help." Sans leaned forwards in his chair. He knew that if he'd had magic it would be burning in him now but all he felt was an empty ache. That would have to do.

"I trust you do, Sans. But I'm not sure you understand what you're asking for. I came here today to convince you otherwise." Gaster's dark eyesockets seemed unspeakably sad.

Unable to contain his agitation, Sans stood up and stuck his hands in the front pockets of his lab coat. He could feel his amiable grin slide into a grimace but there was nothing he could do.

"if you'n asgore don't have the guts for it, that's fine. but i'm gonna make sure paps sees the sky one day. no matter how bad of a person that makes me."

Gaster looked away and the two of them stayed very still for a long moment. Inside his pockets, Sans' hands were balled into fists to make them stop shaking. The lights in his eyes were cold specks of fire.

"I see. I was afraid of this." Gaster whispered, his hands starting to fidget in little nervous tics. "You're too determined for your own good, Sans."

There was a long, thin sigh and Gaster looked older than Sans had ever seen him.

"You will be working covertly from now on, and more closely with me in the lower Labs. There is... a lot I haven't told you, and I trust you will not breathe a word of it to anyone. Especially Papyrus."

Sans didn't even bother with responding, they both knew he'd take these secrets to his grave. And there was nothing he wanted more than to keep Papyrus safe and innocent.}}}}}

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{{{{{Working in the lower labs was rewarding in a way that Sans' previous work had never been. A low, thrumming energy suffused the winding corridors and filled him with a sort of frantic energy.

Working with his father directly now, Sans was amazed to discover just how brilliant the old skeleton actually was.

Sans had always considered himself to be very smart, but beside Gaster he was like the glittering gems of Waterfall compared to actual night sky. The way the taller skeleton's mind worked was baffling at times and he seemed to reach conclusions practically out of thin air, forcing Sans to scramble to keep up. He'd stopped sleeping almost entirely now and returned home to Papyrus only when his guilt became too much to bear.

Work on the CORE was almost complete and the hulking machine now sat half-built in the Hotland lava sea. Sans felt the dry updrafts from the molten rock make his lab coat flap around his knees as he stood looking at it beside his Father. They had built this. Now they just needed to power it.

"U-uhm D-Doctor Gaster, if you would please s-sign here?" A tremulous voice appeared to Sans' left. He recognized it.

"alphys?" Sans asked, his grin tilting up at the edges. She stared at him for a moment, holding the pen and clipboard to her chest nervously as if she were having trouble recognizing him.

"S-Sans? O-oh! Sorry, Sir!" She squeaked and handed the items over for Gaster's signature. The tall skeleton's eyes were still fixated on the CORE as he signed. Gaster had taken to wearing a black lab coat now, to make himself distinguishable from the rank-and-file scientists working on the CORE. Alphys was still looking at Sans almost expectantly, as if waiting for him to crack a joke?

No puns were forthcoming.

"s'good to see you, al. any luck on that robot idea?" Sans felt bad that they hadn't ever gotten together after graduation to catch up, but time has a way of sneaking up on you.

"N-no..." She looked a little disappointed. "I could b-bore you with the specifics all day, heh heh... heh. but uh- no. Y-your work is much cooler." She was sweating as she accepted the clipboard back from Gaster. "W-well I'll see you... I guess?"

Alphys turned and tromped off as quickly as her short legs would carry her, almost getting bowled over by another messenger who was running the opposite way

"Doctor Gaster!" Cried the Royal Guardsman, a young-sounding lizard monster covered head-to-toe in oversized black armor. Sans could smell his sweat from where he stood, even over the stench of brimstone. "T-there's been a human sighting!"

That definitely made Gaster tear his eyes from his creation. The poor guard seemed to shrink under Gaster's intense gaze.

" _keep your voice down_." Sans hissed, approaching the guard despite his stink. "tell me where."

"I-I'm only supposed to say to the D-Doctor." The stammered, shivering in the sweltering heat.

"Sans can hear anything you have to say to me." Gaster stated, gritting his teeth nervously at the sudden news. "Quickly, now." He prompted. Sans leaned in closer.

"The Ruins, Sir. It's in the Ruins of Home." The Guard said.

Once the guard had fled back the way he'd come Gaster turned to Sans, the depths of his concern finally surfacing on his face. He put both his hands on his son's shoulders and held him tighter than he probably meant to.

"You don't have to go." Gaster whispered, little lights appearing in his normally dark eyesockets. They trembled in the blackness, like his fingers were on Sans' shoulders.

"don't worry, dad. the human won't even know anything's wrong until i get her to you. this is why we built the soul-extraction chambers, so i won't be in danger." Sans tried to reassure his dad. He raised a hand when it looked like Gaster was about to object.

They'd argued round and round about why Gaster should be the one to confront any human that wandered into the Underground, but Sans had always found some excuse or other. He felt like he needed to prove that he was strong enough to do this alone, not even to Gaster or anyone else, but to himself.

"I know, I know. But remember the blasters, okay?" Gaster pleaded, shedding all of the imperiousness he'd exuded earlier. Sans would remember the blasters, that's for damn sure. The little mobile cannons they'd modeled off the energies clinging to Chara's corpse, though mainly off the qualities tenacious to endure even after death. Namely, their hatred and their LOVE. The one time Sans had used them before as practice, he'd ended up on the floor in agony. He could still remember the barbed rage that had sunk its jaws into him after firing even one.

Sans just nodded in response and turned away. He'd get the human's soul no matter what, he vowed.}}}}}

.

{{{{{The ragged creature that stepped shyly through the purple stone threshold ahead gave Sans pause. He'd always remembered humans as being so much... _bigger._ But that must have been because he'd barely been more than a toddler when they'd all gotten shut into the underground. Sans was fully grown now despite his gangliness, and nearly the height of an adult human male.

At least the disguise Gaster had given him made him look a bit more substantial than he actually was. The hugely oversized blue hoodie with its fur lining and cloaking charms gave him a little extra girth but also made him look like he was wearing someone else's pyjamas. Sans sighed and ducked behind a nearby pillar.

A red ribbon was tied back the human's dirty yellow hair, revealing round eyes that darted feverishly, searching for any sign of a threat. The way the child (he assumed it was a child because of their short stature and striped dress) was gripping a little wooden blade made Sans wary of approaching, remembering just how deadly humans could be if provoked. One solid hit would be all it would take for him to...

"Are you hurt, my child?" A new voice chimed, sweet as sunshine and hopeful as a new day. Sans ducked back behind his pillar before he could be spotted lurking. Behind his back, he could hear the mystery voice speaking quietly to the human child. The voice was familiar to Sans, but he just couldn't place it. The child mumbled something back and the new voice gave an excited squeak. Sans' curiosity was killing him but thankfully the duo decided now would be a good time to leave the room.

 _what's a talking monster doin' down here? i thought there was just-_

-RIBBIT-

The human paused as a friendly-looking Froggit blocked their path. The owner of the other voice seemed to have gone ahead for now, foolishly leaving this dangerous creature unsupervised.

For whatever reason, the Froggit clan had decided to remain in the Ruins and would often cause mischief for unwary travelers. Sans got a bad feeling when the child moved to put their toy blade between themselves and the harmless monster, edge tipped forward. A little pale-blue heart appeared over their chest and Sans' eyesockets widened in appreciation.

Even from his hiding place behind a pillar Sans could _feel_ it. For a skeleton who could sense neither heat nor cold, he felt his bones go stiff and chilly. That sort of power could drive the CORE for generations, he realized. Or better yet, free them all.

-RIBBIT?-

The Froggit hopped at the child once, causing the kid to scream and fall back as its rear fin clipped their soul. Sans clapped his palm over his mouth to keep himself from shouting as the small human shrieked its displeasure and raised the weapon.

 _oh god!_

A hollow noise echoed in the purple corridor that was quickly borne away on a sudden gust of wind. Red leaves rustled in the corners of the hallway and the pile of dust spread out across the floor, twinkling in the purplish light.

Humming sweetly, the human kicked the dust a little, as if confused by it, then shrugged and skipped along into the door of the room closest to Sans. Only once they'd left did he allow himself to fall to his knees in shock, burying his face into the lining of his hoodie to muffle his terrified breathing.

 _it killed that Froggit! for no reason but it'd scared them!_ Sans felt the GasterBlasters tugging at the back of his mind, begging to be let out and to right this wrong. To _kill_ the human and exact Judgement. It would be what they deserved.

Shakily raising to his feet again, Sans followed after the child. He was terrified of what might happen if this human got free of the Ruins.}}}}}

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{{{{{Sans didn't know what to do with his hands so he shoved them into the pockets of his massive hoodie like he would have if it were his lab coat. He wondered vaguely if Gaster had even considered his size when making the garment, but lately it was getting harder to tell where or even _when_ his father's mind was at any given moment. Working with quantum mechanics had that effect on a monster.

Oh, he really hoped he'd never end up actually being able to fill this coat properly. He just couldn't imagine it.

Realizing he was getting distracted as well, Sans focused on silently following the human through the Ruins. The mysterious voice from earlier had yet to make a reappearance but Sans didn't doubt they would. That voice had held so much compassion it was hard to imagine it would just leave a child alone down here forever, even a murderous _freak_ of a child.

As he'd watched, the human had systematically slaughtered each and every unsuspecting monster it had encountered, earning more and more LOVE with every swipe of its blade. And it was still giggling sweetly.

Despite being dust up to its elbows in monster remains, the human seemed to be thoroughly enjoying itself and was grinning hugely. Sans knew he didn't have much time before they reached the end of the tunnels and didn't even want to think about what would happen then. What if it should meet Papyrus?

It was that horrible notion that finally drove Sans to act despite his overpowering fear. He would not be able to take the child all the way to New Home, that much was perfectly clear. Luckily, he'd created a contingency plan for this: Well, it was really just a glass jar with a magical coating and power supply. _hey! sometimes simple is best, alright?_

The room ahead boasted a simple lever puzzle that Sans recognized. It involved falling through the ground into one of six rooms, only one of which actually contained the lever required to exit. After picking a room, you could climb back out of a window in the wall and try another one, hopefully with better results. Sans held his breath as the yellow-haired beast looked around, testing the floor with careful feet and pausing to read the instructions plaque on the wall. Sans always preferred his puzzles without instructions, when he could be bothered to build one that is.

Luckily the child did not pick the hole that would give them the solution, instead falling into the lower-left room. Acting quickly, Sans summoned one of the dreaded Blasters but instead of firing it, just crammed it bodily into the room's escape-hole.

'sorry, bud." Sans said to the semi-sentient weapon, which just looked back at him with a mildly-hurt expression and a low whine. "sit tight while i finish this, okay? uh... _stay_." He commanded, trying to look serious in a hoodie about ten sizes too big. At least the Blaster did not question him.

There was a muffled shriek that brought Sans back to the matter at hand. Carefully he lowered himself onto the edge of the crumbling ground where the child had just fallen through. He was ready to jolt backwards, just in case.

"heya, bucko." Sans grinned into the dark room below, pupils barely more than pinpricks of light. "what'sup? you stuck?" He had to stop himself from grinding his teeth as the meek-looking human donned their most pathetic, mercy-inducing expression and nodded. Their wild hair was sloppier now after a particularly hard hit they'd taken earlier which had loosened the ribbon. Sans was pretty ambivalent about kids, but he could see why those puppy-dog eyes would work to great effect on other monsters.

"aw, that's too bad." Sans grinned wider and finally the human realized he was toying with her. Those puppy-dog eyes turned into cold pits of anger in an instant.

"Let me out!" They cried in an imperious tone. It almost reminded Sans of the way the royal family down here spoke, sure that their commands would be obeyed. Too bad Sans wasn't feeling so obliging.

At that moment, however, an unsuspecting Vegetoid decided to surface in the same room as the human was. It popped out of the ground and spooked when confronted by the bizarre scene of the human, a skeleton in the ceiling and a giant goat skull shoved into the exit hole.

"hey! get outta here!" Sans shouted at the carrot-monster which was only starting to look more agitated. The human smiled fiercely at it and stepped forward.

Sans could only watch as the human traded blows with the surprisingly feisty carrot, earning just as many knocks as they could dish out with their wooden blade. Once, a stray magical-potato-bullet took an odd bounce off the wall and cracked the human in the back of the head hard enough to knock the ribbon loose entirely.

Infuriated, the human just started laughing hysterically and in two more hasty slashed of their blade dispatched the monster in a puff of dust.

Every instinct was screaming at Sans to _run_. _Now_. He couldn't stop this child alone. He needed to get help. His father could...

 _wait._

 _calm down_.

There was no way he'd go back to his daddy with his tail between his legs, begging for help like some babybones. He might not have magic, but his mind was a better weapon anyways, Sans decided.

"you're not lookin' so hot, kiddo." Sans arranged his grin carefully before turning back to the child in the pit. It carried just the perfect mix of condescension and cheekiness. "what, did you bite off more than you could chew with that last fight?"

Sans was almost surprised to hear the joke pass his teeth, it had been so long since he'd used humor in self-defense.

"so you gonna heal or just sit there and _leek_ your wounds?" Sans probed, trying to see what sort of items the child had on them. When the human just stared back up at him sullenly through curtains of their loose, yellow hair his question was answered for him. The kid was low on health and had no way out.

 _now what_?

Sans lamented the fact that his only Blaster was being used as a plug. What was he supposed to do? Throw stones? He had a feeling he would give out long before the child did with his feeble throwing arm. Maybe Papyrus was right and he really should get more exercise.

He could wait until another monster showed up and killed her for him? No. How many monsters would have to get dusted all because of his cowardice and weakness? If only he could form magical bones like his brother could, he could end this right here!

But Sans could be patient.

A low giggle startled Sans and he looked down into the hole again carefully. The child was _laughing_. The small creature, looking deranged with its wild hair and cruelly smiling lips sent another chill through Sans that had nothing to do with the cold aura of their soul. Before long the child was laughing uproariously, head thrown back and little white teeth gleaming in their open red mouth.

Sans had been about to turn away when a low rumbling in the ground alerted him of another Vegetoid about to emerge, no- _two_ this time! The child didn't stop laughing even for a moment as she swung her little knife blindly, trying to dodge in the small space but failing. Startled and scared for this strange creature's well-being, the Vegetoids tried to heal the small human by tossing little vegetables at them, but they only served to damage her further.

She twisted and dove, laughing all the while as her blade sliced the air more and more wildly. The smaller of the carrot-monsters seemed ready to surrender but the other moved to protect its kin.

One well-placed corn-cob cracked the ice-blue surface of the human's soul.

"s-stop!" Sans cried and the Vegetoids paused to watch the graceless skeleton clamber down into the pit with them. "that's enough. go now." Sans fell the last meter to the ground but quickly found his feet again. The bigger Vegetoid shot him a nasty glare as if to ask him why he hadn't intervened sooner and Sans felt well-earned shame wash over him. He had nearly allowed the human to kill this monster! What had he been thinking? Thankfully, the carrot-monsters took this moment to submerge again.

Pushing down his ugly emotions, Sans approached the prone human carefully. It seemed even smaller now, with delicate, hairless arms of warm flesh that were curved to protect their breaking soul. The blue heart was barely glowing now and Sans knew he had to act quickly. Pulling the Soul-Capture-Jar-Mark-I from his oversized hoodie (another use besides slight cloaking and being super comfy) he positioned the open end carefully over the human's chest to engulf their soul.

Then he flipped a switch on the device surrounding the lid and let the science happen.

With a sort of pathetic keening noise the human tried to roll away, but they were weak enough that Sans was easily able to hold them still.

"s'okay buddy. it's almost over." Sans mumbled, surprised at the sudden lump in his throat. Why had he wanted to do this? What had he been trying to prove again? The human began struggling more as the ties connecting their body and soul started to stretch and snap and Sans was forced to sit on them to keep them still.

Again and again he repeated "s'almost over, s'almost over, s'almost over."

Sans slammed the lid back onto the jar the moment the child's struggles stopped and fell back against the wall of the dank little pit, as far away from the corpse as he could get. Beside him, he heard the Blaster gave a little questioning bark before disappearing back into the space between times.

Alone at last but for the little soul, Sans broke down.}}}}}

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{{{{{The last thing Sans heard as he stepped out of the Ruins into the blowing wind of Snowdin was a scream. Or at least it started as one but quickly tapered off into a wail that make him feel like something was crawling on his spine. It echoed briefly in the crisp air before the Ruins doors shuddered briefly before slamming shut. Sans tried to open them again out of curiosity but found them barred by powerful magic.

Sans shrugged in his giant hoodie and pulled out the soul again, admiring it in the light. It was still glowing dimly, but the crack which had been forming down the center had fused up again as Sans' device pumped it full of healing energy. It was strange to him that such a peaceful-looking thing could be capable of such wanton murder. But what could you expect from a _human_? They were dangerous beasts and if he had his way they'd all get put down once Monsterkind re-took the surface. Sans didn't actually _hate_ the humans, it was simply a matter of safety. Monsters could never live in peace while they existed.

After changing back into his work-clothes Sans entered the lab complex again, feeling strangely out of place for once. He kept the soul-jar tucked up under his ribs to hide it from prying eyes and the sheer power of it was making his bones tingle.

"Sans!" W.D. Gaster cried as the shorter skeleton appeared in the doorway of his private office. The old monster was on him in an instant, long hands holding his skull gingerly and examining him for any signs of damage.

"c'mon dad. i'm fine." Sans lied behind his grin. "i'm _touched_ , really." The little pun at Gaster's grabby hands went unnoticed.

When Sans pulled the soul-in-a-jar from under his shirt he couldn't help but feel a certain pride. Gaster's eyesockets widened and those little lights appeared in their depths again as the older skeleton drank in the sight of it.

"May I?" Gaster actually asked Sans' permission before taking it from him, which made Sans' grin widen a little. If he could feel this was after taking a human's soul, Sans could feel a little better about the Hell it was to actually take one.

After admiring the soul and transferring it to the permanent soul-extraction chamber to run tests, Gaster swung around again to face Sans. The creaky smile on the old skeleton's face actually suited him very well and it made Sans' soul ache to remember how long it'd been since he'd seen it there.

"I also have something you will like." Gaster grinned with a twinkle in his eyesockets. Something for _Sans_? Immediately his curiosity was piqued as Sans followed his dad over to one of the side work-benches. "I made an incredible breakthrough today regarding powering the CORE. And actually, it was Papyrus who helped me." Gaster chuckled.

Sans was confused when all Gaster handed him was a paper cut-out of a blue heart.

"dad? s'just a soul." Sans stated, feeling left behind as usual.

"Not 'just' a soul!" Gaster was practically beaming, looking more like Papyrus than Sans had ever seen him. "Unfold it!"

Sans followed the directions and realized that the craft was actually multiple layers of paper attached on either end to make a chain of soul-hearts. He held the short chain at arm's length, trying to divine what incredible breakthrough Papyrus' paper-craft could possibly herald. He was about to ask for clarification but Gaster couldn't contain himself any longer.

"Don't you see?" Gaster asked, taking the craft and re-folding it, then unfolding it out again. "We can power the CORE with only _one soul!_ The answer's in the timelines!"

Sans' eyesockets widened at the implications of this. Gaster was telling him to finally pursue his life's calling. He was going to invent time-travel!}}}}}

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What could possibly go wrong?

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 **Hope you guys enjoyed this chapter! Writing Sans-PreVoid!Gaster dynamics was a lot of fun. I like to think that Gaster acted a lot like Sans was around people he loved, trying to shield them from his darker moods.**

 **Also, when considering how Sans' encounters with the human children would go, I'm going to try and make their conflicts match up with the virtues each human soul was supposed to signify. The first (not counting Chara) child's virtue was Patience, so Sans defeats her by being patient since that's really all he's capable of doing right now. The other 5 children in order are: Bravery, Integrity, Perseverance, Kindness and Justice. So look forward to that!**

 **EDIT: Yes, I know that those traits apply to the children themselves and not the manner in which they die. I'm just using them as inspiration.**

 **.**

 **But you know what time it is, don't you, Dear Readers! It's time to announce the next AU! Drum roooollllllllllllll!**

 **Drrrrrrrrrrr...**

 **rrrrrrrrrrrrrrrrrrrrrrrr...**

 **rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr...!**

 **BROMALGAMATE!**

 **(I hope you're all pleased with yoourselves ;_; )**

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 **It will probably be a little while until I can get the first Bromalgamate Chapter out since I'm going to be very busy this week with the StarWars premiere and a number of parties I'll be attending ;P but expect the first part on SATURDAY or SUNDAY at the latest!**


	17. Chapter 17- BROMALGAMATE PT1

**WHEW what a wild week ^o^ sorry it took so long to get this chapter out, but I've been out to around 2AM every night since all my friends got off classes. I've already seen the new Star Wars movie twice and so help me God if you haven't watched it already you need to leave right now and do so.**

 **Okay, so for those of you remaining I hope you like this chapter :) There's a good deal of sitting around and angst but I think you'll like where this arc is going. Because the Bomalgamate AU is so open-ended (really it's just a design concept) I decided to go in a bit of an unexpected direction with it. You'll see ;)  
**

 **Credit for this AU goes to Moofrog and Sushinfood on tumblr!**

 **Also, we get to check back in on the alpha-timeline briefly because I've been neglecting them lol.**

 **And thank you all for your lovely reviews on the last chapter! Can't believe we're at over 180 followers :O I absolutely don't know what to say! Thank you guys so much for your continued support it really helps keep me inspired and determined.**

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WHATEVER CAN HAPPEN WILL

CHAPTER 17- BROMALGAMATE PT.1 - SUNRISE

-into darkness.

Sans felt Papyrus' hand clamp down on his fearfully as the three of them stumbled out of the shortcut into the pitch black space.

"s'okay bro." Sans reassured his little brother, activating his magic and bathing the area in a lurid blue. Immediately, the square contours of work tables and the glassy sheen of lab equipment came into view. Well, at least it was better than the void, but not by much.

Papyrus' fingers relaxed somewhat and Sans wondered when exactly his brave brother had started being afraid of the dark. Then the notion of being trapped in the rubble of a collapsed tower flitted across his mind and Sans shivered.

"Where are we?" Frisk asked, letting go of Sans' hand and moving to examine the nearest desk by the dim light of her own magical eye. The lab- since that's definitely what this was- was completely deserted and very dusty. It shared a similar aesthetic to the True Labs where Sans had worked with his father and later with Alphys but the scale was off. This cavern was immense, with a vaulted ceiling that seemed to stretch forever overhead, and the desks and workspaces weren't crammed into this office but were more spread out to make use of the ample room. Cables snaked along the hewn stone floor, connecting huge ruins of machines to decrepit computers. It was uncomfortably familiar. And yet Sans had never been here.

The air felt strange. If he'd had ear drums Sans was sure they'd be popping.

"not sure." Sans responded finally as he started examining the closest of the hulking contraptions in the meager light. He was still towing Papyrus along by the hand, since neither of them was interested in being without the other even for an instant. "but- oh."

The nearest machine was comprised of an array of prongs and needles all positioned to face an empty, person-sized space in the center. Tubes from the needles ran over the surface of the machine and seemed to empty into a divot where a small canister should fit. The slot was empty now.

Pinned to the control panel on one side was a pile of post-it notes an inch deep, all written in Sans' lazy handwriting. _He'd_ built this scary-looking machine. Or at least some version of him.

'dt compressor mk. viii' read a label painted in other-Sans's script over the sea of notes on the surface of the machine. Sans turned away from it, dragging Papyrus behind him into a more open area where he decided that right about now was a great time for a sit-down.

"Oh." Frisk agreed as she looked over the machine and its attendant notes, then flipped through a dry stack of blueprints on a nearby table before giving up and staring at Sans with a complicated expression. Her mis-matched eyes encompassed him and Papyrus on the floor with their deep intensity, unblinking. "Will you be okay if I go find us something to eat?"

It was hard to tell if Frisk was speaking to both of them or just Sans, but it was clear she was trying to give them some room to talk just the two of them. Sans thanked her for that.

"yeah, kid. see if you can't find us some popato chisps?" Sans grinned, though it felt weak.

"YES. CHISPS SOUND NICE. THANK YOU, HUMAN." Papyrus chattered in his quietest voice (which was still jarring in the expansive silence). There was a steady breeze in the cavern, Sans realized, flowing from one side to the other without exception. It made him uneasy.

"Call me if you need me." Frisk smiled gamely and wandered purposefully off into the darkness.

Sans' eye was starting to hurt from the effort of concentrating his magic into visible form, but he didn't want Papyrus to be in the dark again. Sans cleared his non-existent throat.

"thought you hated junk food." Sans said, grinning. Papyrus made a face at that and shrugged, adjusting into a different position on the rock floor but still looking uncomfortable.

"DESPERATE MEASURES." Papyrus said.

 _yep. definitely uncomfortable._

Sans decided to lay on his back and gestured to Papyrus to use him as a pillow. If he could at least make him more comfortable physically, that was a start. Papyrus' skull and shoulders seemed very light as the lankier skeleton acquiesced and laid back on Sans' magically chubby middle.

For a long time they just stayed like that, being close to each other and organizing their thoughts.

"BROTHER I- _"_

"listen, paps-"

They both tried to speak at once and cut each other off. Sans started chuckling then and the way it bounced Papyrus on his belly made the taller skeleton start laughing too. It was a vicious cycle that made Sans start laughing harder in turn which jostled Papyrus even more and ended with them both in tears, laughing and crying on the floor. Sans rested his palm against Payrus' smooth skull when their mirth died down a little and rubbed little loving circles with his thumb.

"i'm sorry." Sans stated at length, feeling left-over tears running down his temples.

Papyrus shifted on him, not saying anything.

"i'm sorry i couldn't protect you from this. from me, and the shit-show of my life." Sans chuckled dryly and he was glad Papyrus couldn't see his face from this angle. Papyrus sighed quietly and Sans could feel his little brother's boney fingers tighten on the hem of his hoodie. Still Papyrus said nothing, and the way he was angling his face away made Sans afraid. "d'you remember dad now? gaster?"

Papyrus nodded.

"god. s'all so fucked up. don't even know where to start." Sans whispered, wondering how much Papyrus needed to know about the alternate timelines, about Frisk and her abilities. "i lied to you, paps." Sans couldn't keep a hitch from his voice.

Papyrus' fingers tightened further.

"even before everything went 'ta hell... i never told you about my real work. with dad. " It felt weird to call Gaster 'Dad' after everything that had happened but there it was. "i... i d-did some really bad things, paps. i knew you couldn' l-love me if... if you knew."

Sans' breathing had gone funny and his ribs felt tight as a cage around his bifurcated soul.

"SANS." Papyrus said, turning to face him abruptly. Orange tears were streaming down his pale cheekbones. "NOTHING YOU COULD DO. WOULD MAKE ME NOT LOVE YOU."

In a painful bark, Sans sobbed out a noise halfway between a chuckle and a moan. His grin was stretched as tight as it would go on his face and his eyesockets scrunched up in pain. Papyrus sat up slowly and pulled Sans into his lap, letting his older brother cry into his femur as he made little soothing noises and patted Sans' head.

"i- hic- i..." Sans couldn't speak. He wanted to tell Papyrus everything. About the determination experiments. About what had happened to their father. About the children he'd killed in cold blood... but Sans couldn't do it. He wasn't brave enough for that and he knew it.

"YOU HAD YOUR REASONS." Papyrus said, impossibly understanding. Sans didn't deserve a brother like this. A cold pit yawned in his soul as Sans remembered all the years he'd neglected Papyrus, feeding him only the barest scraps of appreciation when he deserved all the love this cruel world could afford. He remembered the times when his creeping apathy had started making him callous, despite his little brother's increasingly desperate attempts to rouse him from his depression. Every morning that Papyrus had shouted him out of bed and dragged him to his sentry post had been an act of love.

Sans had always been too self-centered to appreciate it.

And there was the old, familiar image of kneeling in the flurries outside Snowdin, clutching Papyrus' dusty scarf to his chest and _screaming_...

always _too late_.

Sans' tired sobs redoubled their strength as he buried his face and cried for the pain he'd inflicted with his carelessness.

He didn't know how long they stayed like that.

Eventually though, Sans' tears slowly ran out, leaving him feeling dry and spent. He shivered in his brother's lap, feeling pathetic. He should be the one being strong right now. Papyrus 'ought to be the one being comforted, but Sans had always been the weaker brother.

"my reasons..." Sans mused in a hollow voice. "i'm a coward. that's my _reason_."

Papyrus seemed about to refute that but Sans continued before he could.

"but... you deserve the truth 'bout what's going on. doesn't matter what you think of me." Sans whimpered, rubbing at his eyesockets with the sleeve of his hoodie. Absently he realized that Gaster had made the garment to fit him after all. "dad and i, we worked together on the CORE."

Sans felt Papyrus shift beneath him.

"we needed something to power it, but nothing was strong enough. except souls. human souls, paps." Sans waited for Papyrus to say anything, but when he remained silent Sans carried on. "but something went wrong." Sans couldn't fully remember what _had_ gone wrong, but he knew how it ended: with Gaster shredded until the void consumed him and turned him into... whatever he was now.

"dad... died. and everyone forgot him. except me, i guess. maybe alphys too but she never said anything. things got weird after that, bro. time started doin' weird things. jumping around. stopping. starting up again. an' i was the only one who could remember anything changing." Sans decided to omit Frisk's part in things for now. He didn't want Papyrus to start hating her as badly as he would surely hate him after this conversation.

"s-sometimes... you'd die, paps." Sans said and let that hang in the air for a long while. "it didn' happen to _me_ , so i don't really remember it... but the dreams..."

"YOUR NIGHTMARES." Papyrus said, sounding like he was beginning to understand. Sans was too afraid to look at Papyrus' face so he just nodded, nestled half in his brother's lap pathetically.

"yeah." Sans whispered. "i never appreciated you paps. not like i shoulda'. without you... i just stopped, y'know?"

Papyrus' hand was rubbing Sans' broad back lovingly, something else Sans didn't deserve.

"i don' remember it, but i can still _feel_ it. everything just went black and stopped mattering at all and i _can't_ -" Sans' voice broke but he pushed down the urge to cry again. He needed to explain himself. "i can't do that again."

Without warning Sans found himself lifted by Papyrus' deceptively strong arms and pulled into a deep hug.

"YOU WON'T." Papyrus promised, and Sans truly wanted to believe him.

.

.

Alpha-timeline Alphys sat above the abyss, looking into it fondly. It looked back into her too, but she didn't mind. Her little yellow-scaled feet kicked listlessly in the open air as the endless stream of Waterfall tumbled into it, asking her to join in. She wanted to, but not yet.

First she had to bring Sans and Papyrus home. The human too if she could, but honestly her infatuation with the strange girl had died after everything that had happened.

"Hey NERD. What're you doing?" A voice called from behind her.

Alphys squeaked and nearly lost her balance in her haste to turn around, but a strong arm pulled her to safety. She fell back onto the little dock of wooden planks she'd been sitting on.

Frantically, Alphys stood up and looked around to see where Undyne's - and it _was_ Undyne's- voice was coming from. However, she could not find the tall fish-monster anywhere!

"Uh. Down here?"

Alphys' gaze dropped to below the level of her own height. Oh.

A pale-blue ghost was staring at her quizzically with one eye. It had short, stubby arms in the manner of ghosts but somehow had managed to cross them across its chest. Even more baffling was that it- no, _she_ \- was giving the impression she was tapping her foot impatiently.

"U-undyne?" Alphys peeped, reaching out one clawed hand. It phased right through the ghost.

"In the not-flesh! What's gotten into you, ya weenie?" Undyne said as she activated some sort of magic and Alphys felt the sensation of a hand moving her away from the edge. Alphys realized she'd needed that familiar contact as much as a dying man needs oxygen. She burst into tears.

"W-WOAH! Al, what gives!?" Ghost-Undyne cried as Alphys leaned forwards as if to hug her but simply phased through and landed on her snout. "You look like you've seen a ghost!" Then Undyne realized she'd just made a pun and her simplified ghost-face scrunched up like she'd just bit a lemon.

"How... i-is this p-possible?" Alphys stammered through her tears, picking herself back up gracelessly.

"Uh... what? Girl, I've ALWAYS been a ghost?" Undyne was starting to look really alarmed. Alphys shook her head side-to-side slowly. She _knew_ that Undyne was not a ghost. She could picture her corporeal body perfectly but...

Looking back through her conscious memories, Alphys realized that according to them, Undyne _had_ always been a ghost! She was still the captain of the Royal Guard because of her powerful magic and forceful attitude... but she'd never had a body.

 _This must be how Sans feels all the time_.

A shiver went through Alphys at the thought of living in such constant confusion. No wonder the skeleton-monster was so lethargic and exhausted all the time.

"I'm glad I found you, though." Undyne said, seeming to recover a little. "I had a really bad dream."

.

.

Sans told Papyrus almost everything. He left Frisk out of it wherever he could, but he explained that she had made a mistake in one of the timelines and Gaster had stolen the six human souls. When they had all found Undyne's house in-and-not-in-flames he and Frisk had been drawn in where Gaster had ambushed them and killed them for all intents and purposes.

Papyrus was quick to defend their father, believing that he was not in control of himself. Sans hoped he was right. Indeed they had seen evidence that Gaster still remembered his relationship with his sons by protecting them from Chara-Flowey... but that might not be enough.

Throughout everything, Sans had not been able to meet Papyrus' eyes, though he did have pride enough to sit up on his own.

Still, his hand never left Papyrus'.

"THAT BLACK PLACE WAS REALLY SCARY." Papyrus said, surprising Sans. "IT WAS SO **DARK** THERE. AND IT HURT MY HEAD."

"you were in the void?" Sans asked, still looking away.

"I THINK SO? MAYBE." Papyrus rattled. "BUT IF DAD WAS THERE FOR... WOWIE. A HUNDRED YEARS? OF COURSE THE SCARY GOT INTO HIM."

Sans almost chuckled at the way his brother concisely explained void-madness, but he couldn't find the strength. He was so, so tired.

"yeah. guess so." Sans said.

"SANS." Papyrus seemed tentative. "I'M REALLY HAPPY YOU ARE BUT... HOW ARE YOU STILL ALIVE?"

That did make Sans grin a little.

"that's... a bit of a long story, but i guess i can't a' _void_ ' it forever." Sans' pun was weak and he knew it. Papyrus leaned forward in his peripheral vision.

With a deep sigh Sans turned back towards his tall brother, who was sitting cross-legged with an intense look in his eyesockets. There wasn't any disgust in their depths yet, which was a huge relief, but Sans didn't get his hopes up.

Carefully, Sans positioned his hands to cup the space in front of his chest and concentrated. The blue fire of his eye dimmed and died, briefly bathing them in darkness but not before a red glow began to emanate from between his fingers.

Sans' half-and-half soul emerged slowly from his chest, slipping through the thick fabric of his hoodie without the slightest resistance. Papyrus' eyesockets widened visibly at it, though his brow knitted in concern.

"BUT THAT'S. THE HUMAN'S SOUL?"

Sans nodded, the sight of his maimed soul still a little alarming to him.

"i couldn't die. not while you were still alive." Sans intoned, not taking his eyes from the little glowing heart. "couldn't put you through... that."

Papyrus obviously had a lot of questions, but remained silent.

The even clacking of Frisk's footsteps sounded in the vast cavern then, heralding her return. Sans let his soul drift back into his chest and activated his magic again. To his surprise, however, there was another source of vague light permeating the cave now. It seemed to be coming from further down the cavern, where all the wind was blowing to. It was from that direction that Frisk was approaching them.

Frisk looked concerned about something.

"IS EVERYTHING ALRIGHT, HUMAN?" Papyrus asked, picking up on it as well.

"Yeah." Frisk said, obviously hiding something. The corners of her mouth were struggling to remain neutral but were losing. "Everything's alright. They didn't have any chisps but they had an old ganola brar machine." She tossed them each a few stale bars of some nutty substance which they unwrapped and ate gratefully.

Afterwards, Papyrus stood up, bringing Sans with him since they were still holding hands and looked towards the end of the cavern where it was definitely getting brighter. Sans released his magic and was surprised to discover he could clearly see the contours of his surroundings even without it. He looked to Frisk, who was grinning slightly and cocked a boney brow as she spun on her heel and started walking towards the end of the cavern.

"There's something you guys need to see." She said cryptically, which only made Sans more annoyed. Papyrus obviously held no such reservations and quickly rushed after her.

For a while Sans was forced to focus on keeping up with his tall brother's long strides and was quickly out of breath. In these situations Sans would usually succumb to using his magic to skip every couple steps out of laziness but that wasn't an option with his hand still firmly enclosed in Papyrus' glove.

Sans thanked whatever God there might be when they finally slowed to a stop and he was able to bend forwards and brace his hands on his kneecaps.

"OH. MY GOD." Papyrus said, packing more awe and wonder into those three syllables than most people see in their entire lives.

Sans looked up too.

 _oh._

The valley laid out before them was dark and washed through with deep indigos, violets, greens and the hints of silver where streams snaked down the sides of the mountains. There was a little settlement in the base of the valley speckled with little yellow lights which glimmered through the thick cover of conifers that stood sentry on the innumerable cliffs and ridges and gorges. It seemed to go on forever.

 _ohh..._

Vastly more beautiful was the crystal-clear vault of the dawn sky. Straight ahead of them it was still black and Sans could see the stars. The _actual stars_. They were just littered around like someone had tossed them there. However, Sans knew that what he was witnessing was really the unimaginable infinity of the universe, the cold fire of creation and the emptiness of nothing. Each minuscule white dot twinkled slightly in it is place and Sans wondered how far away they all were. How long ago their light had traveled to grace him with its splendor.

Sans was so glad he'd used up all his tears earlier so they couldn't blur his vision now. He was aware that Frisk was staring at him, but he had eyes only for the sky. It just went on and on and on and on...

For the longest time Sans had come to accept that he would never be lucky enough to see the Surface himself. Too many timelines ended badly for him to get his pessimistic soul to work up the energy for _hope_. There had always been more immediate concerns, like crushing depression. And murderous human children.

The freedom he felt now was intoxicating and he felt his fingers grip Papyrus' tighter in the joy he'd almost forgotten how to feel. Behind Mt. Ebott the sun was rising and its pale rays cut stark shapes in the morning air where they filtered through the pines around them.

"LET'S GO TO THE TOP!" Papyrus shouted, and for once Sans was able to match him in his enthusiasm. They couldn't hold hands while they climbed but that didn't matter. Nothing could hurt them now, not after finally reaching the surface. Everything was going to be fine.

The climb was difficult and Sans was forced to use his magic to keep up with his spider-monkey of a brother, but the exertion was worth it when they both reached the summit. Panting and sweating, Sans stared off into the East where the sun was just beginning to rise.

"WHAT. IS THAT?" Papyrus asked, his voice echoing in the open air.

"that's the sun, bro." Sans said just loud enough to be heard.

"THAT'S THE SUN?" Papyrus thought this over for a few moments. "I LIKE IT."

Sans just smiled. It was a lot like his regular grin, but it felt immeasurably better. Behind them, Frisk was just cresting the final ridge since she still wasn't adept enough at teleportation to use it like Sans did. Breathing heavily she strolled up beside Sans, on the opposite side from Papyrus and joined them in watching the sun rise. The great ball of fire lit the surrounding sky in an aurora or pinks, red and oranges and seemed to turn the thin, low-hanging clouds in the valley into poffs of cotton candy.

"never thought i'd get to see it." Sans whispered, feeling Frisks' soft fingers find his. He still felt bad about hurting her accidentally earlier, but it seemed she didn't mind. Everything was going to be fine.

In his peripheral vision Sans could see Frisk's blue eye gleaming in the light, and by the way her fingers were trembling slightly he was sure she was crying.

"WHAT'S THAT?" Papyrus asked again and Sans grinned.

"i already told you, bro. that's the-"

"The three of you! Get on the ground! NOW!" A familiar voice shouted at them from behind, making them all jump together. Papyrus was clutching Sans' shoulders tightly and Frisk was practically hiding behind his broad back.

"I said GET. ON. THE. GROUND!" Undyne shouted as she leapt up over the last ridge, flew through the air and landed in front of them with a thud you could probably hear down in Snowdin. The muscular fish-monster was wearing a militaristic jacket with plates of plastic armor that reminded Sans of her old guard outfit. However, this get-up looked surprisingly modern and... human. Frisk squeaked a little as Undyne leveled what could only be a gun at the three of them.

"U-UNDYNE?" Papyrus asked uncertainly.

The fish-monster blinked her one eye as she took in the sight of the tall skeleton in his bright-orange scarf and eccentric outfit. Then a cold look fell over her face that told Sans they should probably do as she said.

"c'mon, can't we talk about thi-" Sans only got part-way through his sentence when Undyne struck out with the muzzle of her gun and connected square across Sans' jaw, sending him sprawling.

"SANS!" Papyrus cried and rushed to his brother's side, hands quickly (and painfully) trying to assess the damage. "ARE YOU. ALRIGHT?"

Sans moaned weakly at the blinding pain as he realized his jaw had dislocated. If he hadn't had the HP from Frisk's soul he'd be dead right now, he realized. And Papyrus would've been left alone.

"Stay where you are, IMPOSTORS." Undyne shouted and Sans was aware of her crossing over to Frisk and pushing her down with the skeleton brothers. Around them, the sounds of footsteps and the clatter of armor ringed them in. Cold fire burned in Sans at the injustice of this situation. "The doctor was right, huh? You guys must be the time anomaly he's been looking for. CUFF 'EM!"

Sans struggled feebly as his wrists were bound in hard metal manacles. He looked up to see Frisk and Papyrus receiving the same rough treatment and his eye _burned_.

"Don't you get any ideas, Sans." Undyne rumbled menacingly above him.

He looked up at her, grinning lop-sidedly and with hateful eyesockets.

She just sneered down at him. Then the sole of her black boot connected with his face and the world went black but for the sudden stars that flashed across his vision. Not as good as the real ones, he thought distantly before going unconscious.

.

.

* * *

 **Aahahahaha and you thought everything was going to be fine for a little. ;P You should know better by now, dear readers.**

 **I'm sure you all have some questions about what's going on, such as _who is this doctor Undyne speaks of_? And _why is the Royal Guard still a thing on the Surface_? And most importantly _how much are my feels going to hurt by the end of this arc_? These are all very good questions which I will not be answering at this time. Thank you :)**

 **I'm going to have to slow down on my chapter release schedule since I've got a few art commissions that need to happen, so for this next week I hope to have Pt.2 out by THURSDAY. See you then!**


	18. Chapter 18- BROMALGAMATE PT2

**Some new perspectives in this chapter which I think you guys should like. Some explosions and a bunch of tense conversations in which feelings are had but not much else happens. :**

 **Also a fun rampage at the end. I swear actual Bromalgamate will happen soon!**

 **.**

 **.**

* * *

WHATEVER CAN HAPPEN WILL

CHAPTER 18 - BROMALGAMATE PT.2 - WAR

Emperor Asriel looked down his snout at the sorry trio forced to kneel before his throne. The two skeleton brothers were obviously Sans and Papyrus, though this Sans was currently unconscious. The human he couldn't place.

 _ **That one's Frisk. Be wary.**_

Chara told him, speaking from the darkest part of his mind. It had been a long time since Chara had stirred, let alone spoken and Asriel startled a little despite himself. The fact that his adopted sibling had gone so far as to actually _warn_ him about something... this small human must be a legitimate threat.

Leaning forward slightly, Asriel was pleased by the flash of fear that made itself plain on the adolescent human's face. Her mis-matched eyes were wide behind the obscuring curtain of her bangs and her hands were shaking so much her handcuffs were jingling quietly. Asriel sneered.

 _she doesn't look like much_ , he responded to the voice in his head.

He could feel Chara's annoyance radiating from their shared soul. Burning with such powerful emotion Asriel couldn't help but remember the days when they'd been at the height of their power. The force of their combined rage had blazed in him like a neutron star, burning away his conscience until there was nothing left.

 _ **Heed me, Brother**_.

Chara snapped at him, sending a sharp jolt of pain down his spine that made his claws spasm and chip the ends of his armrests. Fine, if she was going to be that way...

"Alright, Undyne. What am I looking at here?" Asriel faked nonchalance and leaned the bottom of his muzzle into his fist.

The Leader of the Imperial Guard snapped to attention.

"MY MASTER! The Doctor alerted me that his machines had registered a time anomaly. Perhaps the one he's been looking for. These three were caught skulking around Mt. Ebott." Undyne's one yellow eye was squinting suspiciously at the trio, though her posture radiated pride.

"Time anomalies..." Asriel crooned, leaning a bit further forward in his throne. He could feel Chara's curiosity and anticipation sizzling in the base of his skull and it was making it a little hard to concentrate. "So why didn't you bring them directly to him? I have more important matters to attend to. The human _rabble_ has been spotted on the move again."

Undyne visibly deflated at that and her eye flicked back up to him. Asriel knew that in his current form with his darkly tattooed face and wickedly curved horns he could be very intimidating. This Frisk human had gone almost as pale as her skeletal companions looking at him, but there was a curious look in her eyes now that didn't strike him as fear. Maybe Chara was right to be wary.

"I-I thought that you-" Undyne shouted but was cut off.

"Asriel?" Frisk asked. Her small, clear voice seemed to empty the audience chamber of all other noises. Even the courtiers that stuck to the corners of the great hall quieted their constant prattling.

Warm, genuine morning sunlight streamed through patterns cut out of the roof specifically to draw contrast to the old Throne Room in New Home. It slanted through the slightly dusty air and lit the small human in a way that left only her face in shadow. Her palms were open to him, even though they were handcuffed.

The alternate version of Papyrus who was still clutching his brother protectively (and awkwardly since his wrists were also bound) looked up sharply at the human's voice, radiating concern.

"Howdy." Asriel decided to indulge the human a little, if only to slightly annoy Chara. He felt them shift at that and grinned to show his full set of sharp teeth. "But it is _Emperor_ Asriel, human.

Asriel was taken aback slightly when his words did not have their intended effect. Instead of being cowed, the human actually took a step forward!

"H-how?" The human asked in a trembling voice. "How are you alive?"

Undyne was on her before she made it another step, smacking Frisk in the back of the knees with an energy spear and collapsing her with a startled yelp.

"You don't get to talk, WEENIE." Undyne snarled, poising her spear at the human's throat. Asriel's eyes widened, feeling genuinely entertained for the first time in decades. Immortality _could_ be rewarding sometimes. It didn't make sense that this human would think he would be dead, but then he'd always relied on the Doctor for these sorts of things. Maybe in the timeline she came from he had failed in his conquest? He shivered at the thought.

Frisk gulped visibly against the crackling spear, her eyes still fixated on Asriel's. She wanted an answer, he realized.

Asriel snorted disdainfully and waved Undyne away. She complied after a moment, reluctant. Then, in a creaky motion Asriel stood up from his throne and descended from his raised dais. He was still incredibly tall even on level ground, almost as tall as his father though he'd never have Asgore's strength or muscular girth. His horned shadow fell on the human as he approached her.

"I am alive because I am no coward. Wherever time or place you come from I do not know. But _here..._ " Asriel raised a paw to encompass all of Base, the first Surface settlement. Then he made a sweeping gesture to include the entirety of the planet around it, "Here I am God, and all will obey."

Feeling a heady mixture of stolen power and rage fill him, Asriel felt the seven human souls he'd stolen manifest over his chest. The alternate Papyrus cowered, his eyesockets terrified... but the human just kept staring.

"So they tricked you." Frisk stated, possessing the _gall_ to look on him with _pity_! Who was she referring to? Chara? Chara had never _tricked_ him into anything! Sure, he'd had his doubts once they'd reached the Surface so many centuries ago, but he'd been a child then. When he'd wanted to lay down and cry his sibling had urged him onward, filling him with the power to kill instead of meekly being killed. To win the freedom of monsterkind that his own parents would never have the stomach to take for themselves. It had only required six deaths after all. Nothing much in the grand scheme of things, compared to the suffering of an entire race. No, he had not been tricked. He had been shown the way.

He straightened to his full height, feeling the aura of his disastrous magic flow off him and fill the chamber. In the shadows of the room's perimeter the guards and lingering courtiers went very still.

In the oppressive silence the noise of the main doors opening sounded like a mountain grinding its teeth. The guards surrounding the entrance snapped out of their stupor at the noise and turned their pikes on the figures revealed in the threshold.

"hey, what gives?" Sans asked as he sauntered in. The shorter skeleton shot an amused glance at the lowered pikes before brushing them off and moving forward. His younger, taller brother strolled in after him, giving the guards a good-natured but warning look. Sans took in the sight before him and gave a low whistle. "good thing i didn't miss the party," he grinned.

Asriel watched Frisk watch the skeleton brothers approach, trying to gauge her reaction. she seemed fearful, but not confused. She had been in this sort of situation before.

"BROTHER." The familiar Papyrus said, placing a black-gloved hand on his Sans' shoulder and nodding at their doppelgangers. The two skeletons exchanged an entire conversation in a single look that was beyond Asriel's capacity to read but at the end Papyrus seemed reassured, letting his hand drop.

"master, good to see you up and about." Sans said- sarcastically? It was often hard to tell. Still, Chara seemed to hiss in response to the perceived slight. "so these're the anomalies, huh? what's wrong with me?"

Sans stopped a few paces away from the tense standoff and looked down at his double, still unconscious. He sent a dirty look Undyne's way. She returned it right back.

"thought i told you to be careful." He said, monotone. "paps, see what you can do, yeah?"

Papyrus approached the anomaly-skeletons and waited for Undyne to back down before lowering himself to his knees beside them. The thick fabric of his armored, militant jacket and pants bunched around his joints. The lanky alternate-skeleton in his absurd scarf and costume looked rattled to say the least and pulled his unconscious brother towards him sharply. However, he must have jostled the alternate Sans because the chubby skeleton-monster groaned painfully, his dislocated jaw making a sad popping noise. Abject fear clouded the alternate Papyrus's eyesockets and the first hints of orange tears appeared. Frisk looked concerned as well, actually daring to look away from Asriel at his most threatening.

"DON'T. HURT HIM?" The alternate Papyrus chattered pathetically, shaking harder than ever.

Asriel noticed that whereas the skeleton brothers he knew had little boney ridges jutting from their skulls and shoulders like horns, the alternate brothers did not. It made them look a lot more human, Asriel thought distastefully.

"WORRY NOT, PAPYRUS. FOR I, THE GREATEST PAPYRUS. WOULD NEVER HURT HIS BROTHER." Papyrus winked and raised his hands palm out to show he meant no harm. It did not escape Asriel's notice that their Sans was watching the whole exchange like a hawk. He was doing a fine job of seeming uninterested by adjusting the blue arm-band that signified his rank as a General but there was a telltale stiffness to his frame that was ready for action.

The alternate Papyrus seemed to consider this and looked to the human girl for guidance. She nodded almost imperceptibly and that seemed to relax him a bit. Slowly, the alternate Papyrus laid his brother on the stone ground but continued to clutch his hand tightly. The skeleton nodded once jerkily, permission granted.

Papyrus gave his double a genuine smile and set to work at healing. Being such a kind-hearted monster, Papyrus had a natural talent for healing magics, even if he rarely got to use them in his line of work. Sans remained vigilant, his fingers playing unconsciously at the little phials of red liquid lined up along his hip under the fold of his jacket.

"master, i need to take them back to the lab. s'pretty urgent." Sans said, then seeming to notice that he was fiddling with his stash of DT and sticking his hands forcefully into the pockets of his cargo jacket. The bright dots of his pupils met Asriel's deferentially, though his grin seemed a little tight.

"Do so. I tire of this interruption." Asriel swept his long, purple cloak around him as he climbed back up to his throne and reclined in it once again. The courtiers and guards in the room seemed to relax now that he was back to being a fixture of the room instead of an angry God-monster. Sans nodded and motioned for a few of the imperial guards to help escort them from the audience chamber.

Chara watched them go through his eyes, and Asriel grinned.

.

.

Frisk struggled against her handcuffs again as they were led out of Asriel's humid throne room and back into the open, mountain air. The warmth of the sun was welcome and exhilarating, but a brisk wind was chilling her even through her oversized sweater. When would she learn to dress for the weather? She smirked, deciding that would be a completely useless exercise considering the mess she'd made of her life.

The monsters milling around the open space made way for their armed procession, casting suspicious glances.

Papyrus was carrying Sans gingerly through the courtyard, struggling to lift his heavy brother since his arms were still bound at the wrists. Despite being fully healed according to the alternate Papyrus, Sans had apparently decided to remain asleep. Nobody was really surprised about this. God knew that Sans needed the rest.

Alternate Papyrus and Sans had offered to help carry him, but Papyrus had insisted that he could manage it alone.

"I WILL KEEP HIM SAFE." Papyrus had stated. When Frisk had smiled encouragingly at him, his grin in return had seemed tired.

Now they were walking through a main courtyard of the monster encampment, which Alternate Sans had told her was called Base. Of all the monsters in this universe, he seemed the most at-ease around her, though Frisk couldn't imagine why.

"he's got his dad's talent for names, amiright?" Sans snickered, sending her a sidelong glance and a wink.

"Are you... being sarcastic, Sans?" Frisk asked, incredulous. "You hate sarcasm."

Sans seemed to think that over for a moment, but his grin only widened. He barked out a deep laugh. "maybe _he_ does." He gestured to the still-unconsious Sans. "but i've been known to fall into the old sar' _chasm'_ from time to time."

Alternate Papyrus groaned, shaking his head. Apparently some things were universal constants.

The shadow of a huge statue in the middle of the coutyard passed over them as they walked among their armed escort. It depicted Asriel in all his winged glory tearing through a platoon of human soldiers. The humans were dressed in medieval armour, but the metal bent and warped around Statue-Asriel's claws and magical attacks like it was cloth. The way the sun hit the statue's face made his eyes shine as if with magic. This universe was a strange one, Frisk decided.

"WHY HASN'T HE WOKEN UP YET?" The alternate Papyrus asked, jerking a black-gloved thumb back to where Papyrus was struggling to keep up under he's brother's weight. Frisk had wanted to walk with him, but alternate Sans had grabbed her arm and insisted they talk. The flash of blue in his left eye had compelled her to obey.

"hey, if i had someone to carry me you think i'd want to walk around?" Sans said, his expression mock-wistful. "if only _i_ had such an strong, awesome brother."

Frisk watched in slight amusement as the alternate Papyrus puffed up in indignation.

"YOU ARE STRONG ENOUGH. TO WALK WITHOUT MY HELP, SANS. EVEN WITHOUT THE DT." Alternate Papyrus chattered lightly, but there was something else in the glance he gave his brother that Frisk couldn't determine.

 _What does he mean, DT?_

Alternate Sans made a coughing noise that Frisk knew meant he was uncomfortable about something. He pushed his hands deeper into his pockets, hunching slightly. The little boney ridges this Sans had above his temples seemed almost like pulled-back cat ears that gave the impression of being permanently threatened.

"shouldn't joke about that, bro." Alternate Sans whispered, almost so softly Frisk didn't hear.

.

.

The first thing Sans was aware of was that his jaw _fucking hurt._ He tried to open his mouth and say something, but with a sharp click his jaw settled into its joint properly and drowned him in sudden pain.

"aaaaaaagh." He groaned, reaching a hand up to cup his tender jaw. Now that the initial readjustment was done, it didn't hurt nearly as much as he'd expected it to. Still...

 _fucking undyne. you'll regret that._

"SANS! YOU'RE AWAKE?" Sans finally cracked open his eyesockets and was relieved to see his brother's earnest face swim into focus above him. If he was still with Papyrus things couldn't be all bad, he decided.

"ah eel jaahull" Sans slurred, sitting up in his brother's arms. His mouth felt all loose and weird.

"WHAT?" Papyrus asked, concerned. Sans groaned and put his fingers on the edge of his mandible. With a sharp motion he pushed it to the right and almost choked on the sudden jolt of pain. Tears appeared in his eyes as he moved his face, experimenting.

"i feel ' _jaw'ful_." Sans repeated, satisfied to hear he could talk again.

Papryus groaned, but he was smiling more genuinely now. He gently clacked his forehead against the top of Sans' skull and gave him a bear-hug.

"I AM SO GLAD. THAT YOU ARE ALRIGHT." Papyrus told him, making Sans smile too. A little cough off to the side alerted him to the fact that Frisk was there with them too, and he turned to face her.

Her and his alternate self with his alternate brother. Sans' cheekbones warmed in slight embarrassment as he pulled away from his brother's embrace. Still, he kept his hand resting on Papyrus' femur protectively.

"hey. ya know it's creepy to watch someone sleep." Sans said, slipping on his usual grin. "besides, you'd think it'd be pretty _snoring_."

Alternate Sans scoffed and leaned back in the chair he was sitting in, propping his booted feet up on the table. Alternate Papyrus was sitting in his chair normally, crossing his arms over his chest.

"and here i thought we could be buds." Alternate Sans affected a disinterested tone of voice.

 _sarcasm? gross._

Sans quickly took in the brothers' unfamiliar appearances: Military clothes, badges of rank, armored plates. More interesting to him, however, were the little ridges of bone along their skulls and jutting from their shoulders and cervical vertebrae, reminding him of his own GasterBlasters. Also, while the alternate Papyrus looked very much like his own brother, the alternate Sans carried little of Sans' softness. He was still a broad monster, but he seemed solid.

Despite his laid-back posture, it was obvious that Alternate Sans was on-edge. Hyper-vigilant. Sans decided this version of him would make a much better sentry than he ever had and wondered what had been different in this universe to make him this way.

Watching Sans process all this, Alternate Sans rolled his pupils and leaned even further back on his chair. Sans was sure he must be using blue magic to keep himself at that implausible angle.

The room they were in now was small and had that familiar lab aesthetic. The air smelled of ozone and chemicals and he could hear the clatter of working bodies through the thin walls and ceiling which were lined with innumerable pipes and valves. Every once in a while the clomping of boots would sound overhead and then diminish as the wearer rushed off in a hurry. It felt like a military base.

Luckily, Frisk took it upon herself to explain a little of what she'd learned of this universe: Namely, that it was the result of Prince Asriel's plan with Chara succeeding over nine centuries ago. Monsterkind had taken the surface and Asriel was calling himself 'Emperor' now.

Sans couldn't hold back a smirk at that. The pretentious little squirt, how had that crybaby ever managed to pull _that_ off? Sans didn't particularly care though, and Frisk was sparse on the details surrounding it.

"well, if we're all done catching up, it's 'bout time we went to see the Doctor. He should be done his work by now." Alternate Sans finally gave up the ghost and full-out levitated his chair off the floor.

"I thought _you_ were the Doctor." Frisk said, her eyebrows pushing together in that way she had.

Alternate Sans almost fell out of his chair at that, but Alternate-Papyrus steadied him at the last moment, his reflexes lightning-fast. However, in that moment when military-Sans' jacket had lifted up Sans noticed the little row of phials arranged on his doppelganger's hip.

 _liquid determination. and a lot of it, too._

"me? a doctor? heh. haven't been a doctor in a long time, kid." Alternate Sans was actually blushing and Sans wondered if he looked that cuddly when he blushed.

"You still could be, if you applied yourself." A new voice sounded from the doorway- Sans hadn't even realized it had opened. The voice was familiar, but it was strange to hear it without its overtone of _madness_.

Sans' jaw dropped so far it nearly dislocated again.

"DAD?" Papyrus asked, gawking as well.

Gaster, in his regular skeletal form strode into the stuffy room, garbed in a neat lab coat and black slacks. His face seemed placid and was unmarred by the ugly cracks that characterized the Gaster from their own experiences.

"hey dad. ya didn't have'ta come over from your lab." Sans stood up so straight he was practically at attention. It looked weird.

Gaster chuckled.

"Nonsense. I couldn't wait to see them." Gaster's dark eyesockets slipped over Sans, Papyrus and Frisk. "Hello, boys. Nice to meet you."

Sans and Papyrus just blinked, making Gaster's smile droop a little, though he continued gamely.

"I'm very glad we were able to find you before... anything untowards happened. These mountains are not safe for monsters ." Gaster's brow crinkled in such a familiar way it made Sans' soul ache. "There's humans about."

Frisk seemed a little offended at that and huffed from her seat on the floor.

"Why would humans try to hurt us for no reason? What's so dangerous about them?" She asked, shuffling her wrists so that her handcuffs clinked together.

Alternate Sans scoffed at that, drawing her ire onto himself. The broad skeleton's eyesockets went dark and Sans could sense the tug of familiar blue magic push him into the floor slightly.

 _interesting. are his powers so volatile because of the Determination he takes?_

"EVERYTHING." Alternate Papyrus was the one to actually answer the question. He said it without malice, just as a statement of fact. Well, he wasn't exactly _wrong_. Humans were probably the most dangerous species on Earth. Besides, its not like Sans himself had a clear conscience where killing humans was concerned. "HUMANS ARE VERY. VERY. DANGEROUS." Papyrus said this with a peculiar expression, looking equal parts haunted and angry.

"NO THEY AREN'T!" Alpha-Papyrus chattered, back to his regular volume again. "THIS HUMAN. WOULD NEVER HURT A WHINSUM!" Sans saw Frisk wince a little at that, guiltily.

"if you think that, you're a fool." Alternate Sans stepped between the two bickering Papyruses, pupils dim and threatening.

" _ **back off**_ , will ya?" Alpha Sans found himself on his feet, staring down the barrel of a pissed-off, DT-infused Sans. Papyrus was quick to stand with him though he kept behind his brother.

" _ **make me**_ **.** " Alternate Sans stepped forward until they were almost nose-to-nose. Even with his hands bound, Sans figured he still figured he stood a chance if things came to blows because of his half-human soul. However, the sheer _wildness_ of this other Sans' magic made him more than a little nervous.

"Stop it, Sans!" Frisk shouted, quickly getting up herself and moving to push them apart. When her bound hands came close enough to touch, Sans blinked to discover that his doppelganger had already teleported away. Frisk seemed a bit put-off by the other Sans' hasty retreat but stayed clinging to Sans' side, bunching her fingers in his thick hoodie.

"buncha _filthy_ human lovers, huh? knew it was too much to hope for..." The alternate Sans pushed his fists into the pockets of his jacket and gave them an ugly grin. Alternate Papyrus' eyesockets had gone grim as well, though he seemed more uncertain in his anger.

"That really is too bad..." Gaster hummed, tapping his fingertips on the back of a clipboard he'd picked up.

Sans was starting to get confused, and it must have showed.

"WE HAD HOPED. YOU COULD JOIN US IN THE FIGHT." Alternate papyrus said, sounding remorseful. He wasn't looking at them anymore. Now Sans was confused _and_ worried. Never a good combination.

"y'know, one day that human of yours is gonna turn on you. don't be surprised when she does, _human lover_." Alternate Sans grimaced.

The irony of that statement was not lost on Sans, who somehow found the strength for a vicious grin.

"they're not all bad." He said simply. He felt Papyrus shift his weight behind him.

A moment of silence ticked past.

"Such a pity..." Gaster seemed to still be lost in his original train of thought, but Sans recognized the sudden resolve that smoothed his alternate-father's features. They had to get out of here. _Now._ "Perhaps you are not the anomaly I've been tracking. At least if you will not fight you can still be useful. Take them to the rendering chamber, Sans."

All his confusion and worry turned to black fear in an instant, seeing the horrified expression that passed over the Alternate Sans' face at the command. Sans tried to summon his magic, but he only received a dim echo. Something was blocking it.

The more he tried to reach it, the heavier and heavier he felt. It took a moment to realize that it was actually his handcuffs getting heavier, absorbing his blue magic! He lifted them up to his eyesockets and discovered that they were made with the same material he'd been using to fix his time-machine back home. It was space-time-resistant metal.

Alternate Sans obeyed his father, quickly hooking Sans with his blue magic and yanking him forwards along with Frisk and Papyrus who were similarly snared. San's doppelganger's left eye was burning a bright, pure blue that chilled Sans to the marrow.

With one last, angry look back at his father, (who was staring after them with something like disappointment) Sans was dragged out of the room and into the hallway with Papyrus and Frisk behind him. Alternate Sans led the caravan and his militant Papyrus trailed them. Workers scurried out of their way as they marched them to whatever a 'Rendering Chamber' was. Sans really didn't want to find out.

-BOOM-!

The walls shook suddenly and a layer of plaster and dust was knocked loose from the ceiling. Alternate Sans stopped, thank God. Maybe there really was someone looking out for them?

 _some sick, twisted bastard._

-KRAKOOM-!-

The second blast was much, much closer. The concrete wall ahead and to their right exploded inwards in an instant, flooding the corridor with a blinding light. Something hit Sans hard in the teeth, knocking him backwards into Papyrus who staggered under his weight but somehow managed to catch him. He heard Frisk cry out but didn't know where she was.

"papyrus!" Sans heard his own voice shout and it took a moment to process that it wasn't _actually_ his voice. Right behind them, the tunnel had collapsed. Sans couldn't see the other Papyrus anywhere. " _ **paps!**_ "

Before he could even think, Sans felt himself getting pushed forward, even as he watched his double run past them with an expression so far past terror there are no words for it.

Without thinking, he lifted two of the Determination phials from the other Sans' belt. He put them in his pocket.

They were outside in the next disjointed instant and running flat-out. Black smoke filled the air and seemed to be coming from everywhere. Distantly, more explosions resounded that rattled his bones as Sans did his best to keep running. His running form was already terrible and the fact that his arms were bound together did absolutely nothing to help matters.

Behind him, Papyrus gave him another push as they found brief cover behind a sturdy-looking wall.

"What _was_ that?" Frisk cried over the ringing in all their ears (or ear-holes). Papyrus was looking at the sky.

"SAAANS?" He said, pulling his hands to his chest plate.

Sans looked up too.

 _shit_.

In the sky, moving faster than Sans would have thought possible were an array of flying machines with wings like birds but little spinning propellers that made a sound like roaring. They were coming right at them.

They bolted from cover not a moment too late and as one were lifted off their feet by the force of a sudden explosion behind them. Everything was spinning but Sans felt himself getting pulled to his feet. They ran again.

Sweat was pouring down his skull and his breathing was painfully ragged in his ribcage but Papyrus' not-so-gentle urging pushed Sans onwards.

They came to a high fence.

 _shit shit shit!_

There was no way around it that Sans could see. They were trapped. The flying machines were turning around.

"Stop right there!" The trio twisted, backs to the fence as they were confronted by a group of humans. Sans' soul thrummed frantically as he struggled to get his breathing back under control. Another explosion rocked the ground.

The humans raised their guns.

The human who had spoken earlier was standing in the middle of the hemi-circle that was keeping them pinned against the fence. "General Sans," She said, grinning. She was an adolescent girl of middle height, with a lean frame and a determined look in her eyes beneath the war-paint. Her brown hair was cut short and boyish.

"HUMAN?" Papyrus chattered, staying so close to Sans that they were practically one monster. "WHAT ARE YOU DOING?" Papyrus sounded genuinely confused. _oh. he doesn't know what a gun does._

Then the Alternate Frisk's eyes widened as Alpha Frisk jumped in front of the two skeleton-monsters. Sans couldn't see Frisk's expression from his current position, but from the looks on the human soldier's faces it must have been something.

"Don't hurt them!" Frisk cried, standing braced with her legs apart, as if she could shield them from their bullets with nothing but her thin body.

The point of soldier-Frisk's gun wavered.

"You. You're me." Alternate Frisk stated, looking utterly baffled. They _really_ didn't have time for this. The roaring of those flying machines was getting closer and Sans prayed that they would at least have the decency not to bomb their own troops.

The other humans were looking to Alternate-Frisk for guidance.

-RAAAAAAAAAAAAAAAAGHH!-!

Sans tore his gaze from the gun-toting humans and looked back towards the center of Base. A tidal-wave of blue magic surged through him, but it wasn't his.

The human flying-machines dropped another payload of bombs on the monster settlement but they exploded mid-air, catching a few of the machines in their blasts and knocking them from the sky. Something impossibly fast and cyan had skewered clean through them, Sans saw.

Another machine dove lower, trying to give the monsters less time to retaliate before the strike, but something long and whip-like and _made of bone_ smashed it clean in half, followed by another of those bellowing wails and a new blast of blue magic. His bones reverberated with it.

"How did he transform so fast?" Alternate Frisk snapped, motioning for half of her troops to grab Sans, Frisk and Papyrus. He squirmed weakly against the rough treatment, but Sans' attention was still fully focused on the commotion in the Base central courtyard. A piercing boom accompanied by a beam of pure-white light swept through the sky and pulverized a few more machines.

"i think you hurt his paps." Sans whispered, not intending for anyone to hear.

Nonetheless, it seemed that the Alternate Frisk had heard him and then she pushed past his Frisk to stand right in front of him, staring Sans down with those intense eyes of hers. She seemed to be looking into his very soul. Then, an odd expression flickered over her face and she barked an order.

Two humans quickly cut a hole in the wire fence using strange, vibrating blades that made an awful noise and soon they were all rushing out of it and across an open field to the forest beyond.

Daring a look back, Sans saw it: A gigantic creature had reared up over the edges of the square buildings with the head of a GasterBlaster and eyes that burned remorseless blue. It seemed to be grinning as it took one massive, paw-like, skeletal hand and swiped a flying machine out of the sky. Another it caught in its jagged teeth and crunched down. It didn't even seem to notice when the fuselage of the machine exploded right inside its maw.

 _that mouth is designed to channel something way more powerful than that._ Sans would have chuckled if he hadn't been so terrified.

Looking more closely, a small figure was standing on the crown of the massive creature's skull and was hurling spears into the sky with incredible power and accuracy. Then one unseen bomb made it through Undyne's inverted-rain of spears but was stooped as it slammed into a bright green force-field. GasterBlaster Sans roared in a way that sounded uncannily like laughter.

Sans almost tripped as he ran, but was caught by Papyrus' long arms which the tall skeleton had suddenly looped around him, keeping him running even though it was an incredibly awkward position. As the made it to the trees another hollow boom ripped through the air.

Another human had died horribly.

They kept running.

.

.

* * *

 **Woah woah woah! A lot of action in that last bit! This AU is turning into something of an action flick heheh.**

 **Let me know what you guys think! :) Also woah we just passed 200 followers! I am absolutely floored by this. Thank you everyone who's been reading. I love all of you!**

 **Sadly, I don't think I'll be able to do much writing this week with the holidays and all, so I'm gonna try to get the next chapter out by THURSDAY. Happy holidays everyone!**


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